<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2020 Workiva-->
<!--r:54b74ade-0167-45d9-83aa-3a6ff68dd49a,g:d980f9d8-2519-4784-aa9b-3404ad0099fd-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/COVERPAGE" xlink:type="simple" xlink:href="root-20200930.xsd#COVERPAGE"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/COVERPAGE" xlink:type="extended" id="i230b887a47174ab793d3400550fb4d54_COVERPAGE">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityListingsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_ab07afb2-8cd7-4d00-8a07-d715bd932f55" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_DocumentType_ab07afb2-8cd7-4d00-8a07-d715bd932f55" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentQuarterlyReport_e6461d4f-30f4-4047-bcac-d0ea8e4346c5" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentQuarterlyReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_DocumentQuarterlyReport_e6461d4f-30f4-4047-bcac-d0ea8e4346c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_59ef48cf-b3e1-49a2-94fb-4dce8a5f0d34" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_DocumentPeriodEndDate_59ef48cf-b3e1-49a2-94fb-4dce8a5f0d34" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_2e2c30cf-e647-4dc2-88ff-f3b3d416ff0e" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_DocumentTransitionReport_2e2c30cf-e647-4dc2-88ff-f3b3d416ff0e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_e351cc2a-2481-413e-b1eb-5a637d9a7437" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityFileNumber_e351cc2a-2481-413e-b1eb-5a637d9a7437" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_7a8357eb-8970-4c8d-b554-0f3e30f978c3" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityRegistrantName_7a8357eb-8970-4c8d-b554-0f3e30f978c3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_04185f11-7972-44ba-8103-92c9d8372882" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityIncorporationStateCountryCode_04185f11-7972-44ba-8103-92c9d8372882" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_a266404b-e05d-4e18-98ef-d3d17df1bbe7" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityTaxIdentificationNumber_a266404b-e05d-4e18-98ef-d3d17df1bbe7" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_80998492-5d4c-4432-bd7f-af540e880724" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityAddressAddressLine1_80998492-5d4c-4432-bd7f-af540e880724" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine2_60150f9c-414c-4dad-80bc-c6384dedd723" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressAddressLine2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityAddressAddressLine2_60150f9c-414c-4dad-80bc-c6384dedd723" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_8fe61648-c012-4141-8ea4-c17133c9e50b" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityAddressCityOrTown_8fe61648-c012-4141-8ea4-c17133c9e50b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_abe5464f-a9aa-4f76-bfaf-74f3489579a0" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityAddressStateOrProvince_abe5464f-a9aa-4f76-bfaf-74f3489579a0" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_3287bc6e-9134-4962-a2a8-727cb9c6d6b7" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityAddressPostalZipCode_3287bc6e-9134-4962-a2a8-727cb9c6d6b7" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_c72bdb95-e736-4863-97bb-4c43be4d91c6" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_CityAreaCode_c72bdb95-e736-4863-97bb-4c43be4d91c6" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_61cbb373-1606-4e05-8836-e5088cd25a19" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_LocalPhoneNumber_61cbb373-1606-4e05-8836-e5088cd25a19" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_4afcbb6f-053d-4aaf-a126-db148fdba673" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityCurrentReportingStatus_4afcbb6f-053d-4aaf-a126-db148fdba673" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_bfac9724-df1c-4164-88f3-998f555dd7f4" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityInteractiveDataCurrent_bfac9724-df1c-4164-88f3-998f555dd7f4" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_f2e065e1-d059-4402-85bf-38d343f25f87" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityFilerCategory_f2e065e1-d059-4402-85bf-38d343f25f87" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_d6814b38-88eb-4c39-a412-21193e1e464e" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntitySmallBusiness_d6814b38-88eb-4c39-a412-21193e1e464e" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_e0ad8c89-ecb3-41fd-91ac-820d84f7f38b" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityEmergingGrowthCompany_e0ad8c89-ecb3-41fd-91ac-820d84f7f38b" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityExTransitionPeriod_ba860972-fd3b-4362-8eb2-5b1d9400c6ed" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityExTransitionPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityExTransitionPeriod_ba860972-fd3b-4362-8eb2-5b1d9400c6ed" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_8ace4d25-fa8c-4b1f-935c-b37be74893d0" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_Security12bTitle_8ace4d25-fa8c-4b1f-935c-b37be74893d0" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_38ba36be-9fea-4023-a1db-b7f083647991" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_TradingSymbol_38ba36be-9fea-4023-a1db-b7f083647991" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_ef0031ee-403d-4c26-8400-da46eacaa473" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_SecurityExchangeName_ef0031ee-403d-4c26-8400-da46eacaa473" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_b3ce771c-b976-4837-baa7-65975a744988" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityShellCompany_b3ce771c-b976-4837-baa7-65975a744988" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_ab011b51-d987-446f-84bb-bfe0d9b7d5e8" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_ab011b51-d987-446f-84bb-bfe0d9b7d5e8" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_a5c76fcb-1b3a-4729-904e-3f5b370106b9" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_AmendmentFlag_a5c76fcb-1b3a-4729-904e-3f5b370106b9" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_5021a8ac-0929-4509-b643-011ec76863d5" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_DocumentFiscalYearFocus_5021a8ac-0929-4509-b643-011ec76863d5" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_3e4a3894-4f7f-4b3b-81a8-6ea82116f1cd" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_DocumentFiscalPeriodFocus_3e4a3894-4f7f-4b3b-81a8-6ea82116f1cd" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_d05cc695-a738-4336-b8fb-c8f8345a7a42" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityCentralIndexKey_d05cc695-a738-4336-b8fb-c8f8345a7a42" xlink:type="arc" order="29"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_6dff7584-b0ec-4dac-b987-51181c998dcf" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_CurrentFiscalYearEndDate_6dff7584-b0ec-4dac-b987-51181c998dcf" xlink:type="arc" order="30"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityListingsTable_d57a2553-804c-466e-9c9f-21d211081ec3" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityListingsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityListingsLineItems_37de6ae4-e66a-455e-af3c-cd171818447a" xlink:to="loc_dei_EntityListingsTable_d57a2553-804c-466e-9c9f-21d211081ec3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_5b74dcae-2681-4d53-af11-0124703d0e03" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntityListingsTable_d57a2553-804c-466e-9c9f-21d211081ec3" xlink:to="loc_us-gaap_StatementClassOfStockAxis_5b74dcae-2681-4d53-af11-0124703d0e03" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_5b74dcae-2681-4d53-af11-0124703d0e03_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_5b74dcae-2681-4d53-af11-0124703d0e03" xlink:to="loc_us-gaap_ClassOfStockDomain_5b74dcae-2681-4d53-af11-0124703d0e03_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_0550afb1-e9ac-4d56-b310-b6cbb5aee75a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_5b74dcae-2681-4d53-af11-0124703d0e03" xlink:to="loc_us-gaap_ClassOfStockDomain_0550afb1-e9ac-4d56-b310-b6cbb5aee75a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_373366c3-d9fc-4c1c-82a8-ca9f06b423b2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_0550afb1-e9ac-4d56-b310-b6cbb5aee75a" xlink:to="loc_us-gaap_CommonClassAMember_373366c3-d9fc-4c1c-82a8-ca9f06b423b2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_bb57894c-2451-44e8-af23-b620d14f9536" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_0550afb1-e9ac-4d56-b310-b6cbb5aee75a" xlink:to="loc_us-gaap_CommonClassBMember_bb57894c-2451-44e8-af23-b620d14f9536" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSUNAUDITED" xlink:type="simple" xlink:href="root-20200930.xsd#CONDENSEDCONSOLIDATEDBALANCESHEETSUNAUDITED"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSUNAUDITED" xlink:type="extended" id="ic77aef67c7284b3e91fc8d1f2b212712_CONDENSEDCONSOLIDATEDBALANCESHEETSUNAUDITED"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSUNAUDITEDParenthetical" xlink:type="simple" xlink:href="root-20200930.xsd#CONDENSEDCONSOLIDATEDBALANCESHEETSUNAUDITEDParenthetical"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSUNAUDITEDParenthetical" xlink:type="extended" id="ic96fcf02468f4aab8e2672bd8b2d05e2_CONDENSEDCONSOLIDATEDBALANCESHEETSUNAUDITEDParenthetical"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSSUNAUDITED" xlink:type="simple" xlink:href="root-20200930.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSSUNAUDITED"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSSUNAUDITED" xlink:type="extended" id="i026ddd50c48f4cbb957c46516b85612c_CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSSUNAUDITED"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFREDEEMABLECONVERTIBLEPREFERREDSTOCKANDSTOCKHOLDERSDEFICITUNAUDITED" xlink:type="simple" xlink:href="root-20200930.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFREDEEMABLECONVERTIBLEPREFERREDSTOCKANDSTOCKHOLDERSDEFICITUNAUDITED"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFREDEEMABLECONVERTIBLEPREFERREDSTOCKANDSTOCKHOLDERSDEFICITUNAUDITED" xlink:type="extended" id="iaa955a75c6fd4da280ba7be2a8005684_CONDENSEDCONSOLIDATEDSTATEMENTSOFREDEEMABLECONVERTIBLEPREFERREDSTOCKANDSTOCKHOLDERSDEFICITUNAUDITED">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_48be3e7a-8c87-475e-98c3-21f0aeaa3aea" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_99ec055b-32ba-4ae1-81bc-80c39a718c9e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInTemporaryEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_48be3e7a-8c87-475e-98c3-21f0aeaa3aea" xlink:to="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_99ec055b-32ba-4ae1-81bc-80c39a718c9e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_a60c147e-a626-4565-b6ef-1b465458f567" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_99ec055b-32ba-4ae1-81bc-80c39a718c9e" xlink:to="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_a60c147e-a626-4565-b6ef-1b465458f567" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesOutstanding_9ed8e71c-65d9-4095-a399-ab2b1ee995e0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquitySharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_99ec055b-32ba-4ae1-81bc-80c39a718c9e" xlink:to="loc_us-gaap_TemporaryEquitySharesOutstanding_9ed8e71c-65d9-4095-a399-ab2b1ee995e0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_8d54d654-8471-48ef-b8f3-6e827d1ec8d1" xlink:href="root-20200930.xsd#root_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_99ec055b-32ba-4ae1-81bc-80c39a718c9e" xlink:to="loc_root_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_8d54d654-8471-48ef-b8f3-6e827d1ec8d1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_ee54d1e8-01f6-4ac8-9e5b-187b8c903152" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_99ec055b-32ba-4ae1-81bc-80c39a718c9e" xlink:to="loc_us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_ee54d1e8-01f6-4ac8-9e5b-187b8c903152" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_TemporaryEquitySharesTenderOffer_37a765a6-61af-45fd-aa31-f83aa026f2c2" xlink:href="root-20200930.xsd#root_TemporaryEquitySharesTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_99ec055b-32ba-4ae1-81bc-80c39a718c9e" xlink:to="loc_root_TemporaryEquitySharesTenderOffer_37a765a6-61af-45fd-aa31-f83aa026f2c2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_TemporaryEquityStockIssuedDuringPeriodSharesConversionOfSimpleAgreementForFutureEquity_09bff096-72e1-4ca6-adcf-79b6131e3c95" xlink:href="root-20200930.xsd#root_TemporaryEquityStockIssuedDuringPeriodSharesConversionOfSimpleAgreementForFutureEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_99ec055b-32ba-4ae1-81bc-80c39a718c9e" xlink:to="loc_root_TemporaryEquityStockIssuedDuringPeriodSharesConversionOfSimpleAgreementForFutureEquity_09bff096-72e1-4ca6-adcf-79b6131e3c95" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_TemporaryEquityStockIssuedDuringPeriodValueConversionOfSimpleAgreementForFutureEquity_1d0ad569-addd-4f49-9ce7-2357194053ee" xlink:href="root-20200930.xsd#root_TemporaryEquityStockIssuedDuringPeriodValueConversionOfSimpleAgreementForFutureEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_99ec055b-32ba-4ae1-81bc-80c39a718c9e" xlink:to="loc_root_TemporaryEquityStockIssuedDuringPeriodValueConversionOfSimpleAgreementForFutureEquity_1d0ad569-addd-4f49-9ce7-2357194053ee" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesOutstanding_298cdd44-9a12-4361-8049-f9212d5ba756" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquitySharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_d2850c5e-2510-4bc9-9ea2-87316af62dd4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_48be3e7a-8c87-475e-98c3-21f0aeaa3aea" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_cdd97cf7-b3ec-44d7-977c-3ca8f4e86371" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_us-gaap_StockholdersEquity_cdd97cf7-b3ec-44d7-977c-3ca8f4e86371" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_4c2f4085-00f6-4ffa-a007-b4777ba12342" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_us-gaap_SharesOutstanding_4c2f4085-00f6-4ffa-a007-b4777ba12342" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesIssued_4b0c27be-db93-4e33-a115-782c433b78c7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_us-gaap_SharesIssued_4b0c27be-db93-4e33-a115-782c433b78c7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_f68aaf22-64e3-4106-b03d-1e92dff467eb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_us-gaap_NetIncomeLoss_f68aaf22-64e3-4106-b03d-1e92dff467eb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_0e250cfa-c6b1-4bb7-8076-71b166fe4f73" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_0e250cfa-c6b1-4bb7-8076-71b166fe4f73" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_APICTenderOfferAndConversionOfUnitsShares_e278645d-1392-49bb-9663-aa12246679e8" xlink:href="root-20200930.xsd#root_APICTenderOfferAndConversionOfUnitsShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_root_APICTenderOfferAndConversionOfUnitsShares_e278645d-1392-49bb-9663-aa12246679e8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_APICTenderOfferAndConversionOfUnitsValue_f100ac75-022c-4730-9aba-e8d61f641447" xlink:href="root-20200930.xsd#root_APICTenderOfferAndConversionOfUnitsValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_root_APICTenderOfferAndConversionOfUnitsValue_f100ac75-022c-4730-9aba-e8d61f641447" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_b1804452-e33e-4fb4-95d1-e457d382f305" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_b1804452-e33e-4fb4-95d1-e457d382f305" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_a9a24196-bdc6-4538-9a29-32538bfc3981" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_a9a24196-bdc6-4538-9a29-32538bfc3981" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_APICShareBasedPaymentArrangementRecognitionAndExerciseShares_492e67d1-4392-40fd-9260-16a826e5c11b" xlink:href="root-20200930.xsd#root_APICShareBasedPaymentArrangementRecognitionAndExerciseShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_root_APICShareBasedPaymentArrangementRecognitionAndExerciseShares_492e67d1-4392-40fd-9260-16a826e5c11b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions_22b732f7-5e77-495a-951a-f068a263f4b7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationAndExerciseOfStockOptions_22b732f7-5e77-495a-951a-f068a263f4b7" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_025ec7b7-05f5-4830-9832-fbda92378da6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_025ec7b7-05f5-4830-9832-fbda92378da6" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_StockholdersEquitySharesSettlementOfRelatedPartyLoan_e168da58-366c-402a-9a03-0cec5213c626" xlink:href="root-20200930.xsd#root_StockholdersEquitySharesSettlementOfRelatedPartyLoan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_root_StockholdersEquitySharesSettlementOfRelatedPartyLoan_e168da58-366c-402a-9a03-0cec5213c626" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_StockholdersEquityValueSettlementOfRelatedPartyLoan_0763ad1c-990b-41a6-8662-533df70e8fcd" xlink:href="root-20200930.xsd#root_StockholdersEquityValueSettlementOfRelatedPartyLoan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_30c82819-a417-4e29-8ec0-975149baa692" xlink:to="loc_root_StockholdersEquityValueSettlementOfRelatedPartyLoan_0763ad1c-990b-41a6-8662-533df70e8fcd" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesIssued_9ee060fe-3b9f-477a-a3d4-078a27b72bc3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesIssued"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_ae5f77df-485d-4bab-8d89-cbc3586d4749" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_9f032de1-5d68-440f-9270-50d7c4546dd3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_535f7853-0668-4084-8a8c-426d854f0c8b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_48be3e7a-8c87-475e-98c3-21f0aeaa3aea" xlink:to="loc_us-gaap_StatementTable_535f7853-0668-4084-8a8c-426d854f0c8b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_cb9e4035-5cdb-47ec-a7f1-f80ad29ba58f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_535f7853-0668-4084-8a8c-426d854f0c8b" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_cb9e4035-5cdb-47ec-a7f1-f80ad29ba58f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_cb9e4035-5cdb-47ec-a7f1-f80ad29ba58f_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_cb9e4035-5cdb-47ec-a7f1-f80ad29ba58f" xlink:to="loc_us-gaap_EquityComponentDomain_cb9e4035-5cdb-47ec-a7f1-f80ad29ba58f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_a4c115f9-385d-4beb-991b-fb707f8ccaee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_cb9e4035-5cdb-47ec-a7f1-f80ad29ba58f" xlink:to="loc_us-gaap_EquityComponentDomain_a4c115f9-385d-4beb-991b-fb707f8ccaee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_67907742-0307-46d0-8c6d-a97c4d5289f8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_a4c115f9-385d-4beb-991b-fb707f8ccaee" xlink:to="loc_us-gaap_CommonStockMember_67907742-0307-46d0-8c6d-a97c4d5289f8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockMember_18b7804e-bba4-42aa-96df-3cd3c601e124" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_a4c115f9-385d-4beb-991b-fb707f8ccaee" xlink:to="loc_us-gaap_TreasuryStockMember_18b7804e-bba4-42aa-96df-3cd3c601e124" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_190d8063-9cee-4f53-abdb-a3b0533f740b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_a4c115f9-385d-4beb-991b-fb707f8ccaee" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_190d8063-9cee-4f53-abdb-a3b0533f740b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_f75a3d42-9f9b-464a-b411-dcc2f90b949e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_a4c115f9-385d-4beb-991b-fb707f8ccaee" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_f75a3d42-9f9b-464a-b411-dcc2f90b949e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_7e5fec3a-16d5-4e78-aeff-81d22eeca0f1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_a4c115f9-385d-4beb-991b-fb707f8ccaee" xlink:to="loc_us-gaap_RetainedEarningsMember_7e5fec3a-16d5-4e78-aeff-81d22eeca0f1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_2733718d-725d-4d57-a45b-ee90fbd94651" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_535f7853-0668-4084-8a8c-426d854f0c8b" xlink:to="loc_us-gaap_StatementClassOfStockAxis_2733718d-725d-4d57-a45b-ee90fbd94651" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_2733718d-725d-4d57-a45b-ee90fbd94651_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_2733718d-725d-4d57-a45b-ee90fbd94651" xlink:to="loc_us-gaap_ClassOfStockDomain_2733718d-725d-4d57-a45b-ee90fbd94651_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_29846595-f514-46a3-a08d-584951f771ae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_2733718d-725d-4d57-a45b-ee90fbd94651" xlink:to="loc_us-gaap_ClassOfStockDomain_29846595-f514-46a3-a08d-584951f771ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesEPreferredStockMember_41f059b3-b6d0-4c9a-9b20-ef0ebd3b686b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesEPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_29846595-f514-46a3-a08d-584951f771ae" xlink:to="loc_us-gaap_SeriesEPreferredStockMember_41f059b3-b6d0-4c9a-9b20-ef0ebd3b686b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFREDEEMABLECONVERTIBLEPREFERREDSTOCKANDSTOCKHOLDERSDEFICITUNAUDITEDParenthetical" xlink:type="simple" xlink:href="root-20200930.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFREDEEMABLECONVERTIBLEPREFERREDSTOCKANDSTOCKHOLDERSDEFICITUNAUDITEDParenthetical"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFREDEEMABLECONVERTIBLEPREFERREDSTOCKANDSTOCKHOLDERSDEFICITUNAUDITEDParenthetical" xlink:type="extended" id="i32d9a7b435a54082acf35afb6261f8b1_CONDENSEDCONSOLIDATEDSTATEMENTSOFREDEEMABLECONVERTIBLEPREFERREDSTOCKANDSTOCKHOLDERSDEFICITUNAUDITEDParenthetical"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWSUNAUDITED" xlink:type="simple" xlink:href="root-20200930.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWSUNAUDITED"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWSUNAUDITED" xlink:type="extended" id="i74a3c32c131444ba9c718cbd6a233301_CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWSUNAUDITED"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/NATUREOFBUSINESS" xlink:type="simple" xlink:href="root-20200930.xsd#NATUREOFBUSINESS"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/NATUREOFBUSINESS" xlink:type="extended" id="iec526feda5404239a57c050d0ab4a376_NATUREOFBUSINESS"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/NATUREOFBUSINESSDetails" xlink:type="simple" xlink:href="root-20200930.xsd#NATUREOFBUSINESSDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/NATUREOFBUSINESSDetails" xlink:type="extended" id="i71f82bbf956e4864b30e632a031f1e1b_NATUREOFBUSINESSDetails"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/SIGNIFICANTACCOUNTINGPOLICIES" xlink:type="simple" xlink:href="root-20200930.xsd#SIGNIFICANTACCOUNTINGPOLICIES"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/SIGNIFICANTACCOUNTINGPOLICIES" xlink:type="extended" id="ic763dd9398204f44a020868451aaf8a7_SIGNIFICANTACCOUNTINGPOLICIES"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/SIGNIFICANTACCOUNTINGPOLICIESPolicies" xlink:type="simple" xlink:href="root-20200930.xsd#SIGNIFICANTACCOUNTINGPOLICIESPolicies"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/SIGNIFICANTACCOUNTINGPOLICIESPolicies" xlink:type="extended" id="i657b629e422d4289b5a950233f48666d_SIGNIFICANTACCOUNTINGPOLICIESPolicies"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/SIGNIFICANTACCOUNTINGPOLICIESDetails" xlink:type="simple" xlink:href="root-20200930.xsd#SIGNIFICANTACCOUNTINGPOLICIESDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/SIGNIFICANTACCOUNTINGPOLICIESDetails" xlink:type="extended" id="i38fce9f9934c4f66968291b0292e24fc_SIGNIFICANTACCOUNTINGPOLICIESDetails"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/INVESTMENTS" xlink:type="simple" xlink:href="root-20200930.xsd#INVESTMENTS"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/INVESTMENTS" xlink:type="extended" id="ic60888f2a9d244f08050fe4766097b5b_INVESTMENTS"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/INVESTMENTSTables" xlink:type="simple" xlink:href="root-20200930.xsd#INVESTMENTSTables"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/INVESTMENTSTables" xlink:type="extended" id="i2abe07f7d80744fda5275a4a6d38687c_INVESTMENTSTables"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/INVESTMENTSAmortizedCostandFairValueDetails" xlink:type="simple" xlink:href="root-20200930.xsd#INVESTMENTSAmortizedCostandFairValueDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/INVESTMENTSAmortizedCostandFairValueDetails" xlink:type="extended" id="i575dd0dab3494199a9ee0a2cf49aebac_INVESTMENTSAmortizedCostandFairValueDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_bb5f1f6b-996d-461e-9a3c-f2cafc202392" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_c224aeef-1f9d-4a6a-98eb-74a4f3aca85f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_bb5f1f6b-996d-461e-9a3c-f2cafc202392" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_c224aeef-1f9d-4a6a-98eb-74a4f3aca85f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_0a74e36e-1f78-4dcc-a751-c38819b38b07" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_bb5f1f6b-996d-461e-9a3c-f2cafc202392" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_0a74e36e-1f78-4dcc-a751-c38819b38b07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_762171d9-d658-490f-8862-4bb802aad35d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_bb5f1f6b-996d-461e-9a3c-f2cafc202392" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_762171d9-d658-490f-8862-4bb802aad35d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_a448800e-9884-4c1c-993a-1556dd899419" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_bb5f1f6b-996d-461e-9a3c-f2cafc202392" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_a448800e-9884-4c1c-993a-1556dd899419" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_d13fbd57-43e9-4ee0-b48a-1b5f3d1bc623" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_bb5f1f6b-996d-461e-9a3c-f2cafc202392" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_d13fbd57-43e9-4ee0-b48a-1b5f3d1bc623" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_28e30d7d-9d05-4d52-9a6a-070f0161ad66" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_d13fbd57-43e9-4ee0-b48a-1b5f3d1bc623" xlink:to="loc_us-gaap_FinancialInstrumentAxis_28e30d7d-9d05-4d52-9a6a-070f0161ad66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_28e30d7d-9d05-4d52-9a6a-070f0161ad66_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_28e30d7d-9d05-4d52-9a6a-070f0161ad66" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_28e30d7d-9d05-4d52-9a6a-070f0161ad66_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5755d7b9-5da5-44a9-915a-3fee09c9f12b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_28e30d7d-9d05-4d52-9a6a-070f0161ad66" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5755d7b9-5da5-44a9-915a-3fee09c9f12b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasuryAndGovernmentMember_6d016e11-4305-4187-afa8-cb95f27c116a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USTreasuryAndGovernmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5755d7b9-5da5-44a9-915a-3fee09c9f12b" xlink:to="loc_us-gaap_USTreasuryAndGovernmentMember_6d016e11-4305-4187-afa8-cb95f27c116a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MunicipalBondsMember_0d834ece-aab2-43c2-a5df-80694cd7184d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MunicipalBondsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5755d7b9-5da5-44a9-915a-3fee09c9f12b" xlink:to="loc_us-gaap_MunicipalBondsMember_0d834ece-aab2-43c2-a5df-80694cd7184d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_d389176f-ee53-4553-9e06-b561719bfb28" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5755d7b9-5da5-44a9-915a-3fee09c9f12b" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_d389176f-ee53-4553-9e06-b561719bfb28" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_806f596a-3593-4d86-be88-a3ddefc9fd55" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5755d7b9-5da5-44a9-915a-3fee09c9f12b" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_806f596a-3593-4d86-be88-a3ddefc9fd55" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_683c89d3-267a-4a71-9998-06d9542f62f5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5755d7b9-5da5-44a9-915a-3fee09c9f12b" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_683c89d3-267a-4a71-9998-06d9542f62f5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherDebtSecuritiesMember_a752ddc3-c50c-443c-9c41-c643bafcfb48" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5755d7b9-5da5-44a9-915a-3fee09c9f12b" xlink:to="loc_us-gaap_OtherDebtSecuritiesMember_a752ddc3-c50c-443c-9c41-c643bafcfb48" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/INVESTMENTSUnrealizedLossesDetails" xlink:type="simple" xlink:href="root-20200930.xsd#INVESTMENTSUnrealizedLossesDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/INVESTMENTSUnrealizedLossesDetails" xlink:type="extended" id="ided4131b05404c8a9958ee2c93580af1_INVESTMENTSUnrealizedLossesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_7ce0e6a5-fbe3-4a89-b865-d9f100c73b7b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_ef90c619-8d0f-4469-b18d-173457b056a1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_7ce0e6a5-fbe3-4a89-b865-d9f100c73b7b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_ef90c619-8d0f-4469-b18d-173457b056a1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_a01a6d4e-f475-4a51-b36a-ad96c103297c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_7ce0e6a5-fbe3-4a89-b865-d9f100c73b7b" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_a01a6d4e-f475-4a51-b36a-ad96c103297c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_d431839a-4d01-446e-a122-9405fbf8665c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_7ce0e6a5-fbe3-4a89-b865-d9f100c73b7b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_d431839a-4d01-446e-a122-9405fbf8665c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_e185c1f6-8383-4ccd-9fb5-bd3c27f4816b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_7ce0e6a5-fbe3-4a89-b865-d9f100c73b7b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_e185c1f6-8383-4ccd-9fb5-bd3c27f4816b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_353659e9-fce2-4dd4-bfc2-fe29210658e9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_7ce0e6a5-fbe3-4a89-b865-d9f100c73b7b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_353659e9-fce2-4dd4-bfc2-fe29210658e9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_3ae0d3af-8834-4b16-8f2d-76a171046a0c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_7ce0e6a5-fbe3-4a89-b865-d9f100c73b7b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_3ae0d3af-8834-4b16-8f2d-76a171046a0c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTable_ac0cb910-6012-4222-a3e3-e285d1d710f0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_7ce0e6a5-fbe3-4a89-b865-d9f100c73b7b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTable_ac0cb910-6012-4222-a3e3-e285d1d710f0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_d32feedd-7fd4-4de4-b265-2943c24daa48" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTable_ac0cb910-6012-4222-a3e3-e285d1d710f0" xlink:to="loc_us-gaap_FinancialInstrumentAxis_d32feedd-7fd4-4de4-b265-2943c24daa48" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d32feedd-7fd4-4de4-b265-2943c24daa48_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_d32feedd-7fd4-4de4-b265-2943c24daa48" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d32feedd-7fd4-4de4-b265-2943c24daa48_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_499a8e72-8399-46fc-aef2-c3cfe86de648" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_d32feedd-7fd4-4de4-b265-2943c24daa48" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_499a8e72-8399-46fc-aef2-c3cfe86de648" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MunicipalBondsMember_89024e43-9d89-4745-b937-60aa1fa51663" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MunicipalBondsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_499a8e72-8399-46fc-aef2-c3cfe86de648" xlink:to="loc_us-gaap_MunicipalBondsMember_89024e43-9d89-4745-b937-60aa1fa51663" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_cd097aaf-3399-4b28-bc9a-bd05ff8ec86a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_499a8e72-8399-46fc-aef2-c3cfe86de648" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_cd097aaf-3399-4b28-bc9a-bd05ff8ec86a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_ea1a548f-12f1-492e-abad-ac66f9e13fb4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_499a8e72-8399-46fc-aef2-c3cfe86de648" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_ea1a548f-12f1-492e-abad-ac66f9e13fb4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_afc28c4c-e285-41bc-acc7-a4291411c17f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_499a8e72-8399-46fc-aef2-c3cfe86de648" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_afc28c4c-e285-41bc-acc7-a4291411c17f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherDebtSecuritiesMember_caa0026f-7dcf-4e09-87d1-9939ee8e21bc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_499a8e72-8399-46fc-aef2-c3cfe86de648" xlink:to="loc_us-gaap_OtherDebtSecuritiesMember_caa0026f-7dcf-4e09-87d1-9939ee8e21bc" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/INVESTMENTSContractualMaturityDetails" xlink:type="simple" xlink:href="root-20200930.xsd#INVESTMENTSContractualMaturityDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/INVESTMENTSContractualMaturityDetails" xlink:type="extended" id="i3b580b4a13554010afab435b6232cba8_INVESTMENTSContractualMaturityDetails"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/INVESTMENTSNarrativeDetails" xlink:type="simple" xlink:href="root-20200930.xsd#INVESTMENTSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/INVESTMENTSNarrativeDetails" xlink:type="extended" id="i7f74ea829a624293892762ea87a64e72_INVESTMENTSNarrativeDetails"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/INVESTMENTSNetInvestmentIncomeDetails" xlink:type="simple" xlink:href="root-20200930.xsd#INVESTMENTSNetInvestmentIncomeDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/INVESTMENTSNetInvestmentIncomeDetails" xlink:type="extended" id="i3239c96da8a4411f973b0319c5433eb0_INVESTMENTSNetInvestmentIncomeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_8270956b-433a-4f9c-807f-81034b95050e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossInvestmentIncomeOperating_036bfb23-bda3-4739-a61a-87bba874acb4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GrossInvestmentIncomeOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_8270956b-433a-4f9c-807f-81034b95050e" xlink:to="loc_us-gaap_GrossInvestmentIncomeOperating_036bfb23-bda3-4739-a61a-87bba874acb4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInvestmentExpense_f33228fc-32f3-44e6-981e-5200e17c1163" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentIncomeInvestmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_8270956b-433a-4f9c-807f-81034b95050e" xlink:to="loc_us-gaap_InvestmentIncomeInvestmentExpense_f33228fc-32f3-44e6-981e-5200e17c1163" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentIncome_dd5cd9a8-13cd-4e1c-b21a-b10dbd6c88c1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetInvestmentIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_8270956b-433a-4f9c-807f-81034b95050e" xlink:to="loc_us-gaap_NetInvestmentIncome_dd5cd9a8-13cd-4e1c-b21a-b10dbd6c88c1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_8a348632-20fd-4d32-a163-e4d253ee94b3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_8270956b-433a-4f9c-807f-81034b95050e" xlink:to="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_8a348632-20fd-4d32-a163-e4d253ee94b3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_a7185b89-6728-4462-a437-bb278d332a62" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_8a348632-20fd-4d32-a163-e4d253ee94b3" xlink:to="loc_us-gaap_InvestmentTypeAxis_a7185b89-6728-4462-a437-bb278d332a62" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_a7185b89-6728-4462-a437-bb278d332a62_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_a7185b89-6728-4462-a437-bb278d332a62" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_a7185b89-6728-4462-a437-bb278d332a62_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_8cb7e5f9-5986-4926-9d99-76c94949f758" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_a7185b89-6728-4462-a437-bb278d332a62" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_8cb7e5f9-5986-4926-9d99-76c94949f758" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BondsMember_1f177faf-977e-4cc5-b467-fda522404141" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BondsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_8cb7e5f9-5986-4926-9d99-76c94949f758" xlink:to="loc_us-gaap_BondsMember_1f177faf-977e-4cc5-b467-fda522404141" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsMember_ba445eee-3270-4e4c-87c0-1e21007b8f2f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_8cb7e5f9-5986-4926-9d99-76c94949f758" xlink:to="loc_us-gaap_CashAndCashEquivalentsMember_ba445eee-3270-4e4c-87c0-1e21007b8f2f" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/INVESTMENTSCreditRatingsDetails" xlink:type="simple" xlink:href="root-20200930.xsd#INVESTMENTSCreditRatingsDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/INVESTMENTSCreditRatingsDetails" xlink:type="extended" id="i082a4d86066641b99f001745ceeca9c7_INVESTMENTSCreditRatingsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_1b4c6ad6-030d-44a5-9e31-cd7594be7c10" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_7f23ac21-0a9a-4ebf-90a7-09262b4a3198" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_1b4c6ad6-030d-44a5-9e31-cd7594be7c10" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_7f23ac21-0a9a-4ebf-90a7-09262b4a3198" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_81b8215c-1c4a-4d4e-8ee4-24268904a8f6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_1b4c6ad6-030d-44a5-9e31-cd7594be7c10" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_81b8215c-1c4a-4d4e-8ee4-24268904a8f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_51cabb4c-abab-4140-944c-bd57400a0e05" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_1b4c6ad6-030d-44a5-9e31-cd7594be7c10" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_51cabb4c-abab-4140-944c-bd57400a0e05" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_dba015cd-5956-45ad-a341-1d85a8d7dd60" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_1b4c6ad6-030d-44a5-9e31-cd7594be7c10" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_dba015cd-5956-45ad-a341-1d85a8d7dd60" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CreditRatingStandardPoorsAxis_1bde863f-79a4-449d-b9b7-d7fc423b5709" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CreditRatingStandardPoorsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_dba015cd-5956-45ad-a341-1d85a8d7dd60" xlink:to="loc_srt_CreditRatingStandardPoorsAxis_1bde863f-79a4-449d-b9b7-d7fc423b5709" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ExternalCreditRatingStandardPoorsMember_1bde863f-79a4-449d-b9b7-d7fc423b5709_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ExternalCreditRatingStandardPoorsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CreditRatingStandardPoorsAxis_1bde863f-79a4-449d-b9b7-d7fc423b5709" xlink:to="loc_srt_ExternalCreditRatingStandardPoorsMember_1bde863f-79a4-449d-b9b7-d7fc423b5709_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ExternalCreditRatingStandardPoorsMember_a98708b7-84d7-4f93-a1c6-67f478757db6" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ExternalCreditRatingStandardPoorsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CreditRatingStandardPoorsAxis_1bde863f-79a4-449d-b9b7-d7fc423b5709" xlink:to="loc_srt_ExternalCreditRatingStandardPoorsMember_a98708b7-84d7-4f93-a1c6-67f478757db6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StandardPoorsAAARatingMember_dea600ac-e351-4780-9417-aa25f3ded396" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StandardPoorsAAARatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ExternalCreditRatingStandardPoorsMember_a98708b7-84d7-4f93-a1c6-67f478757db6" xlink:to="loc_srt_StandardPoorsAAARatingMember_dea600ac-e351-4780-9417-aa25f3ded396" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_StandardPoorsAAPlusAAAAMinusAMinusOneRatingMember_9e427369-d408-40bf-bd1e-8037e23e9003" xlink:href="root-20200930.xsd#root_StandardPoorsAAPlusAAAAMinusAMinusOneRatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ExternalCreditRatingStandardPoorsMember_a98708b7-84d7-4f93-a1c6-67f478757db6" xlink:to="loc_root_StandardPoorsAAPlusAAAAMinusAMinusOneRatingMember_9e427369-d408-40bf-bd1e-8037e23e9003" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_StandardPoorsAPlusAAMinusRatingMember_c0d5a943-7199-4ee6-96ee-8f273fc1a620" xlink:href="root-20200930.xsd#root_StandardPoorsAPlusAAMinusRatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ExternalCreditRatingStandardPoorsMember_a98708b7-84d7-4f93-a1c6-67f478757db6" xlink:to="loc_root_StandardPoorsAPlusAAMinusRatingMember_c0d5a943-7199-4ee6-96ee-8f273fc1a620" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_StandardPoorsBBBPlusBBBBBBMinusRatingMember_9281527a-4821-4dd9-8616-753ed1bdb5f5" xlink:href="root-20200930.xsd#root_StandardPoorsBBBPlusBBBBBBMinusRatingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ExternalCreditRatingStandardPoorsMember_a98708b7-84d7-4f93-a1c6-67f478757db6" xlink:to="loc_root_StandardPoorsBBBPlusBBBBBBMinusRatingMember_9281527a-4821-4dd9-8616-753ed1bdb5f5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_eb099739-bec7-448d-a155-ef2dd24afe97" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_dba015cd-5956-45ad-a341-1d85a8d7dd60" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_eb099739-bec7-448d-a155-ef2dd24afe97" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_eb099739-bec7-448d-a155-ef2dd24afe97_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_eb099739-bec7-448d-a155-ef2dd24afe97" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_eb099739-bec7-448d-a155-ef2dd24afe97_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_49828f67-339a-44d2-ad20-c8c11c794a7c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_eb099739-bec7-448d-a155-ef2dd24afe97" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_49828f67-339a-44d2-ad20-c8c11c794a7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesMember_142ced91-ddbf-4eb2-a139-dddc6aadd06d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableforsaleSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_49828f67-339a-44d2-ad20-c8c11c794a7c" xlink:to="loc_us-gaap_AvailableforsaleSecuritiesMember_142ced91-ddbf-4eb2-a139-dddc6aadd06d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_dc97736a-d42b-40d0-a348-1510b559ceee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_dba015cd-5956-45ad-a341-1d85a8d7dd60" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_dc97736a-d42b-40d0-a348-1510b559ceee" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_dc97736a-d42b-40d0-a348-1510b559ceee_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_dc97736a-d42b-40d0-a348-1510b559ceee" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_dc97736a-d42b-40d0-a348-1510b559ceee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_446a0f9c-e190-438f-81b5-92cbe9fb3d9f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_dc97736a-d42b-40d0-a348-1510b559ceee" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_446a0f9c-e190-438f-81b5-92cbe9fb3d9f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_CreditRatingConcentrationRiskMember_e96ec1e7-f4f7-49d2-92af-b49d549f5b57" xlink:href="root-20200930.xsd#root_CreditRatingConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_446a0f9c-e190-438f-81b5-92cbe9fb3d9f" xlink:to="loc_root_CreditRatingConcentrationRiskMember_e96ec1e7-f4f7-49d2-92af-b49d549f5b57" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/FAIRVALUEOFFINANCIALINSTRUMENTS" xlink:type="simple" xlink:href="root-20200930.xsd#FAIRVALUEOFFINANCIALINSTRUMENTS"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/FAIRVALUEOFFINANCIALINSTRUMENTS" xlink:type="extended" id="i061a88fc3507449e95aca270c725b04f_FAIRVALUEOFFINANCIALINSTRUMENTS"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSTables" xlink:type="simple" xlink:href="root-20200930.xsd#FAIRVALUEOFFINANCIALINSTRUMENTSTables"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSTables" xlink:type="extended" id="i5bd51467283f40a5a278f65a0d48533f_FAIRVALUEOFFINANCIALINSTRUMENTSTables"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSBalanceSheetGroupingDetails" xlink:type="simple" xlink:href="root-20200930.xsd#FAIRVALUEOFFINANCIALINSTRUMENTSBalanceSheetGroupingDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSBalanceSheetGroupingDetails" xlink:type="extended" id="i3bbdd914183447b9b9bb8eb19f8abf7e_FAIRVALUEOFFINANCIALINSTRUMENTSBalanceSheetGroupingDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_db78e973-0b25-408f-a095-a3244134eda2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_9075ca5f-0931-449a-b8df-4c4c5ca906c0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_db78e973-0b25-408f-a095-a3244134eda2" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_9075ca5f-0931-449a-b8df-4c4c5ca906c0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_97dd4346-05d8-40a5-8941-c3cc0e91683e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_9075ca5f-0931-449a-b8df-4c4c5ca906c0" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_97dd4346-05d8-40a5-8941-c3cc0e91683e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_97901454-3d4e-4da0-97eb-c9214068cee6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_9075ca5f-0931-449a-b8df-4c4c5ca906c0" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_97901454-3d4e-4da0-97eb-c9214068cee6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_1bf06977-03a0-49d2-8a90-67a8d71a66bf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_9075ca5f-0931-449a-b8df-4c4c5ca906c0" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_1bf06977-03a0-49d2-8a90-67a8d71a66bf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_a1f636c7-c9df-4078-947e-3db3e714cf90" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_db78e973-0b25-408f-a095-a3244134eda2" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_a1f636c7-c9df-4078-947e-3db3e714cf90" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantsAndRightsOutstanding_f67067b3-ddde-4e87-baae-95efe786e8cb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WarrantsAndRightsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_a1f636c7-c9df-4078-947e-3db3e714cf90" xlink:to="loc_us-gaap_WarrantsAndRightsOutstanding_f67067b3-ddde-4e87-baae-95efe786e8cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialLiabilitiesFairValueDisclosure_ae8eecf9-7b9b-43ae-a9f3-dc777073707b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialLiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_a1f636c7-c9df-4078-947e-3db3e714cf90" xlink:to="loc_us-gaap_FinancialLiabilitiesFairValueDisclosure_ae8eecf9-7b9b-43ae-a9f3-dc777073707b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_91e68de1-1d5f-41ec-84f4-2d9820f3d836" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_db78e973-0b25-408f-a095-a3244134eda2" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_91e68de1-1d5f-41ec-84f4-2d9820f3d836" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_c8d5e7bb-aa8e-4f64-9131-7f026fe53842" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_91e68de1-1d5f-41ec-84f4-2d9820f3d836" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_c8d5e7bb-aa8e-4f64-9131-7f026fe53842" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c8d5e7bb-aa8e-4f64-9131-7f026fe53842_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_c8d5e7bb-aa8e-4f64-9131-7f026fe53842" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c8d5e7bb-aa8e-4f64-9131-7f026fe53842_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_850205ac-e498-4e59-9284-5620a7837417" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_c8d5e7bb-aa8e-4f64-9131-7f026fe53842" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_850205ac-e498-4e59-9284-5620a7837417" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_5008d86b-e685-4f30-b3fc-f620cd2446f9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_850205ac-e498-4e59-9284-5620a7837417" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_5008d86b-e685-4f30-b3fc-f620cd2446f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_54af4beb-a098-40a6-8cd8-7ba939488f76" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_850205ac-e498-4e59-9284-5620a7837417" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_54af4beb-a098-40a6-8cd8-7ba939488f76" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_b2da34e5-2a4d-4401-bc38-f231f9d6bbeb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_850205ac-e498-4e59-9284-5620a7837417" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_b2da34e5-2a4d-4401-bc38-f231f9d6bbeb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_a046538b-1a1e-4f00-8521-b989160770c0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_91e68de1-1d5f-41ec-84f4-2d9820f3d836" xlink:to="loc_us-gaap_FinancialInstrumentAxis_a046538b-1a1e-4f00-8521-b989160770c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_a046538b-1a1e-4f00-8521-b989160770c0_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_a046538b-1a1e-4f00-8521-b989160770c0" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_a046538b-1a1e-4f00-8521-b989160770c0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_1f311f0c-9bae-4fab-9f5f-025e46c84b65" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_a046538b-1a1e-4f00-8521-b989160770c0" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_1f311f0c-9bae-4fab-9f5f-025e46c84b65" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedMaturitiesMember_67c8a4e0-111c-41cb-82af-028f02092371" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FixedMaturitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_1f311f0c-9bae-4fab-9f5f-025e46c84b65" xlink:to="loc_us-gaap_FixedMaturitiesMember_67c8a4e0-111c-41cb-82af-028f02092371" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_4b5adcc6-72a3-4f6f-bf35-e45ab6cb6caa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_1f311f0c-9bae-4fab-9f5f-025e46c84b65" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_4b5adcc6-72a3-4f6f-bf35-e45ab6cb6caa" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSNarrativeDetails" xlink:type="simple" xlink:href="root-20200930.xsd#FAIRVALUEOFFINANCIALINSTRUMENTSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSNarrativeDetails" xlink:type="extended" id="ifc20ad8ecc814d5880b2324cc563a068_FAIRVALUEOFFINANCIALINSTRUMENTSNarrativeDetails"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSLongTermDebtDetails" xlink:type="simple" xlink:href="root-20200930.xsd#FAIRVALUEOFFINANCIALINSTRUMENTSLongTermDebtDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSLongTermDebtDetails" xlink:type="extended" id="ic3c4d123f3534a71a087d89ebfc637bb_FAIRVALUEOFFINANCIALINSTRUMENTSLongTermDebtDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_e830a9f7-dc16-44c8-b7c0-a15e9fdae097" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_2387f9e2-a1a0-48de-8fd7-a57bed1098e3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_e830a9f7-dc16-44c8-b7c0-a15e9fdae097" xlink:to="loc_us-gaap_LongTermDebtFairValue_2387f9e2-a1a0-48de-8fd7-a57bed1098e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_49b670c5-9ec8-49d3-b890-edcf7937093d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_e830a9f7-dc16-44c8-b7c0-a15e9fdae097" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_49b670c5-9ec8-49d3-b890-edcf7937093d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_fe3f3ebf-d38f-4f45-a84c-230e0b47eee5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_49b670c5-9ec8-49d3-b890-edcf7937093d" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_fe3f3ebf-d38f-4f45-a84c-230e0b47eee5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_fe3f3ebf-d38f-4f45-a84c-230e0b47eee5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_fe3f3ebf-d38f-4f45-a84c-230e0b47eee5" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_fe3f3ebf-d38f-4f45-a84c-230e0b47eee5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_16910428-4620-468b-88d9-d9ac772a0f2f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_fe3f3ebf-d38f-4f45-a84c-230e0b47eee5" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_16910428-4620-468b-88d9-d9ac772a0f2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_f6452036-f94d-443e-a5c2-650b956cb460" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_16910428-4620-468b-88d9-d9ac772a0f2f" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_f6452036-f94d-443e-a5c2-650b956cb460" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_39ab5cd1-e3a4-41cd-9da9-5dabecdcf8b9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_49b670c5-9ec8-49d3-b890-edcf7937093d" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_39ab5cd1-e3a4-41cd-9da9-5dabecdcf8b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_39ab5cd1-e3a4-41cd-9da9-5dabecdcf8b9_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_39ab5cd1-e3a4-41cd-9da9-5dabecdcf8b9" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_39ab5cd1-e3a4-41cd-9da9-5dabecdcf8b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_67db6763-d715-4438-8acc-d75c071ff7a9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_39ab5cd1-e3a4-41cd-9da9-5dabecdcf8b9" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_67db6763-d715-4438-8acc-d75c071ff7a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_03c90363-1103-4fda-8f4c-c876f537bffd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_67db6763-d715-4438-8acc-d75c071ff7a9" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_03c90363-1103-4fda-8f4c-c876f537bffd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_dee3c7be-34f0-44a1-b242-3b6ee67a6ea2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_03c90363-1103-4fda-8f4c-c876f537bffd" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_dee3c7be-34f0-44a1-b242-3b6ee67a6ea2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_b888f844-1833-4039-bf6d-0fdf7633ecdc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_03c90363-1103-4fda-8f4c-c876f537bffd" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_b888f844-1833-4039-bf6d-0fdf7633ecdc" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/LOSSANDLOSSADJUSTMENTEXPENSERESERVES" xlink:type="simple" xlink:href="root-20200930.xsd#LOSSANDLOSSADJUSTMENTEXPENSERESERVES"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/LOSSANDLOSSADJUSTMENTEXPENSERESERVES" xlink:type="extended" id="if3f2d535204c470a95bf0f538754bfaa_LOSSANDLOSSADJUSTMENTEXPENSERESERVES"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/LOSSANDLOSSADJUSTMENTEXPENSERESERVESTables" xlink:type="simple" xlink:href="root-20200930.xsd#LOSSANDLOSSADJUSTMENTEXPENSERESERVESTables"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/LOSSANDLOSSADJUSTMENTEXPENSERESERVESTables" xlink:type="extended" id="i195dbf611bae45caba1f4f0ff290b199_LOSSANDLOSSADJUSTMENTEXPENSERESERVESTables"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/LOSSANDLOSSADJUSTMENTEXPENSERESERVESDetails" xlink:type="simple" xlink:href="root-20200930.xsd#LOSSANDLOSSADJUSTMENTEXPENSERESERVESDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/LOSSANDLOSSADJUSTMENTEXPENSERESERVESDetails" xlink:type="extended" id="i3e5e440c3cf44785b2cc2285355532a8_LOSSANDLOSSADJUSTMENTEXPENSERESERVESDetails"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/LONGTERMDEBT" xlink:type="simple" xlink:href="root-20200930.xsd#LONGTERMDEBT"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/LONGTERMDEBT" xlink:type="extended" id="i24b205b4b7234d0d80f1eba1e95b3a65_LONGTERMDEBT"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/LONGTERMDEBTTables" xlink:type="simple" xlink:href="root-20200930.xsd#LONGTERMDEBTTables"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/LONGTERMDEBTTables" xlink:type="extended" id="iafaa6e4484e6498fa4a7b7248ee755c6_LONGTERMDEBTTables"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/LONGTERMDEBTScheduleOfDebtDetails" xlink:type="simple" xlink:href="root-20200930.xsd#LONGTERMDEBTScheduleOfDebtDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/LONGTERMDEBTScheduleOfDebtDetails" xlink:type="extended" id="i8706e99e6e964bef9c210b61c4ffadc7_LONGTERMDEBTScheduleOfDebtDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_286174fa-0f3c-4787-a51f-2564b31769af" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_bf84f8c3-da62-4cb5-9b61-03a90d3118d7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_286174fa-0f3c-4787-a51f-2564b31769af" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_bf84f8c3-da62-4cb5-9b61-03a90d3118d7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPayableCurrentAndNoncurrent_397be927-5f83-40ea-8819-25d824b190e0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_286174fa-0f3c-4787-a51f-2564b31769af" xlink:to="loc_us-gaap_InterestPayableCurrentAndNoncurrent_397be927-5f83-40ea-8819-25d824b190e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_3ea130b7-12a9-4021-b8a2-3cce76edc583" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_286174fa-0f3c-4787-a51f-2564b31769af" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_3ea130b7-12a9-4021-b8a2-3cce76edc583" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_6be03886-2a1f-4e5f-84d1-3506e46ae515" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_286174fa-0f3c-4787-a51f-2564b31769af" xlink:to="loc_us-gaap_LongTermDebt_6be03886-2a1f-4e5f-84d1-3506e46ae515" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_244b3c19-f3a7-4493-ba67-5a78dd11c1c0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_286174fa-0f3c-4787-a51f-2564b31769af" xlink:to="loc_us-gaap_DebtInstrumentTable_244b3c19-f3a7-4493-ba67-5a78dd11c1c0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_48200a87-4f94-4ea8-9d1a-69284b0e8ef3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_244b3c19-f3a7-4493-ba67-5a78dd11c1c0" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_48200a87-4f94-4ea8-9d1a-69284b0e8ef3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_48200a87-4f94-4ea8-9d1a-69284b0e8ef3_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_48200a87-4f94-4ea8-9d1a-69284b0e8ef3" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_48200a87-4f94-4ea8-9d1a-69284b0e8ef3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_53d867cd-4fb8-49af-a08a-1a6532bea134" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_48200a87-4f94-4ea8-9d1a-69284b0e8ef3" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_53d867cd-4fb8-49af-a08a-1a6532bea134" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_7116d8a3-ab26-4ebd-a1fb-c824a81767ed" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_53d867cd-4fb8-49af-a08a-1a6532bea134" xlink:to="loc_us-gaap_SecuredDebtMember_7116d8a3-ab26-4ebd-a1fb-c824a81767ed" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantMember_1eeded9f-4d27-4d3e-8b7e-11db51bbf8e2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_53d867cd-4fb8-49af-a08a-1a6532bea134" xlink:to="loc_us-gaap_WarrantMember_1eeded9f-4d27-4d3e-8b7e-11db51bbf8e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_234f6cca-723a-4e64-86db-d7d3685b4ca5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_244b3c19-f3a7-4493-ba67-5a78dd11c1c0" xlink:to="loc_us-gaap_DebtInstrumentAxis_234f6cca-723a-4e64-86db-d7d3685b4ca5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_234f6cca-723a-4e64-86db-d7d3685b4ca5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_234f6cca-723a-4e64-86db-d7d3685b4ca5" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_234f6cca-723a-4e64-86db-d7d3685b4ca5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_b261cbe7-2c57-4d72-913f-6ee41256f26a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_234f6cca-723a-4e64-86db-d7d3685b4ca5" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_b261cbe7-2c57-4d72-913f-6ee41256f26a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_TermLoanAMember_24e779fb-d040-4a72-a236-27d773dd47f8" xlink:href="root-20200930.xsd#root_TermLoanAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b261cbe7-2c57-4d72-913f-6ee41256f26a" xlink:to="loc_root_TermLoanAMember_24e779fb-d040-4a72-a236-27d773dd47f8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_TermLoanBMember_755dd590-e3e7-40e8-9854-b85bbd0480f1" xlink:href="root-20200930.xsd#root_TermLoanBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b261cbe7-2c57-4d72-913f-6ee41256f26a" xlink:to="loc_root_TermLoanBMember_755dd590-e3e7-40e8-9854-b85bbd0480f1" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/LONGTERMDEBTNarrativeDetails" xlink:type="simple" xlink:href="root-20200930.xsd#LONGTERMDEBTNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/LONGTERMDEBTNarrativeDetails" xlink:type="extended" id="icdce2ed24984413abdc1c30a9b0df4fa_LONGTERMDEBTNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_d87917cc-20ef-42a7-bacb-97443ca04ab8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_973c5990-2de6-47f4-9b27-918b2374c4e8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d87917cc-20ef-42a7-bacb-97443ca04ab8" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_973c5990-2de6-47f4-9b27-918b2374c4e8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_f320d3d9-03b1-4d14-9dbe-290b066c1e35" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d87917cc-20ef-42a7-bacb-97443ca04ab8" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_f320d3d9-03b1-4d14-9dbe-290b066c1e35" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_92ff0b9b-b1b5-40ae-b830-0cb4813c26e0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d87917cc-20ef-42a7-bacb-97443ca04ab8" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_92ff0b9b-b1b5-40ae-b830-0cb4813c26e0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_LineOfCreditFacilityFeeOnAverageDailyAmountPercentage_600e4141-a7fd-4e1c-b654-6528050cd5b0" xlink:href="root-20200930.xsd#root_LineOfCreditFacilityFeeOnAverageDailyAmountPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d87917cc-20ef-42a7-bacb-97443ca04ab8" xlink:to="loc_root_LineOfCreditFacilityFeeOnAverageDailyAmountPercentage_600e4141-a7fd-4e1c-b654-6528050cd5b0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_LineOfCreditFacilityFrontingFeePercentage_cba0c3ba-7d34-4f2d-a84e-a4b4a83c4f6e" xlink:href="root-20200930.xsd#root_LineOfCreditFacilityFrontingFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d87917cc-20ef-42a7-bacb-97443ca04ab8" xlink:to="loc_root_LineOfCreditFacilityFrontingFeePercentage_cba0c3ba-7d34-4f2d-a84e-a4b4a83c4f6e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_63a31033-e116-43bb-95a0-2441467513e4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d87917cc-20ef-42a7-bacb-97443ca04ab8" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_63a31033-e116-43bb-95a0-2441467513e4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateIncreaseDecrease_65178e4a-ff64-4902-936a-cef155b4f8ff" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d87917cc-20ef-42a7-bacb-97443ca04ab8" xlink:to="loc_us-gaap_DebtInstrumentInterestRateIncreaseDecrease_65178e4a-ff64-4902-936a-cef155b4f8ff" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_4d1e1e5a-bb4b-4a76-832b-b3fdf49ab37b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d87917cc-20ef-42a7-bacb-97443ca04ab8" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_4d1e1e5a-bb4b-4a76-832b-b3fdf49ab37b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPayableCurrentAndNoncurrent_3c2b7ff2-c055-4763-8751-d33ba4a812fb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d87917cc-20ef-42a7-bacb-97443ca04ab8" xlink:to="loc_us-gaap_InterestPayableCurrentAndNoncurrent_3c2b7ff2-c055-4763-8751-d33ba4a812fb" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_af00b4cf-7ba1-46f9-b557-750f080d3ebc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d87917cc-20ef-42a7-bacb-97443ca04ab8" xlink:to="loc_us-gaap_DebtInstrumentTable_af00b4cf-7ba1-46f9-b557-750f080d3ebc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_100f45e1-ef9c-4eeb-a307-b77b67011532" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_af00b4cf-7ba1-46f9-b557-750f080d3ebc" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_100f45e1-ef9c-4eeb-a307-b77b67011532" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_100f45e1-ef9c-4eeb-a307-b77b67011532_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_100f45e1-ef9c-4eeb-a307-b77b67011532" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_100f45e1-ef9c-4eeb-a307-b77b67011532_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_88f1f59f-91b3-4787-809e-8b420ad67078" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_100f45e1-ef9c-4eeb-a307-b77b67011532" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_88f1f59f-91b3-4787-809e-8b420ad67078" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_cdeb944c-e2a2-4dba-90f3-5c17c6045ad9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_88f1f59f-91b3-4787-809e-8b420ad67078" xlink:to="loc_us-gaap_SecuredDebtMember_cdeb944c-e2a2-4dba-90f3-5c17c6045ad9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_355e3841-712d-4c7a-a74a-19ab4c0025b1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_88f1f59f-91b3-4787-809e-8b420ad67078" xlink:to="loc_us-gaap_LineOfCreditMember_355e3841-712d-4c7a-a74a-19ab4c0025b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_6d1f8a05-ad52-44d3-ab94-204a876b53be" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_af00b4cf-7ba1-46f9-b557-750f080d3ebc" xlink:to="loc_us-gaap_DebtInstrumentAxis_6d1f8a05-ad52-44d3-ab94-204a876b53be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_6d1f8a05-ad52-44d3-ab94-204a876b53be_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_6d1f8a05-ad52-44d3-ab94-204a876b53be" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_6d1f8a05-ad52-44d3-ab94-204a876b53be_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_cb4d6e9c-843a-4880-9b50-a0550a2d3095" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_6d1f8a05-ad52-44d3-ab94-204a876b53be" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_cb4d6e9c-843a-4880-9b50-a0550a2d3095" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_AmendedTermLoanAMember_1d9e82e7-ffcf-468e-bdc7-81f51dbeb14c" xlink:href="root-20200930.xsd#root_AmendedTermLoanAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_cb4d6e9c-843a-4880-9b50-a0550a2d3095" xlink:to="loc_root_AmendedTermLoanAMember_1d9e82e7-ffcf-468e-bdc7-81f51dbeb14c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_AmendedTermLoanBMember_8abbcbc0-36df-4375-af40-b44694b29a42" xlink:href="root-20200930.xsd#root_AmendedTermLoanBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_cb4d6e9c-843a-4880-9b50-a0550a2d3095" xlink:to="loc_root_AmendedTermLoanBMember_8abbcbc0-36df-4375-af40-b44694b29a42" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_a60f2053-6f90-407c-9774-fc76f2729042" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_af00b4cf-7ba1-46f9-b557-750f080d3ebc" xlink:to="loc_us-gaap_CreditFacilityAxis_a60f2053-6f90-407c-9774-fc76f2729042" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_a60f2053-6f90-407c-9774-fc76f2729042_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_a60f2053-6f90-407c-9774-fc76f2729042" xlink:to="loc_us-gaap_CreditFacilityDomain_a60f2053-6f90-407c-9774-fc76f2729042_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_0d59bb9a-88d4-4d35-96d1-cf3a99e35c7d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_a60f2053-6f90-407c-9774-fc76f2729042" xlink:to="loc_us-gaap_CreditFacilityDomain_0d59bb9a-88d4-4d35-96d1-cf3a99e35c7d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_70fe078e-1ecc-4000-99d4-e284fdd5c99e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_0d59bb9a-88d4-4d35-96d1-cf3a99e35c7d" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_70fe078e-1ecc-4000-99d4-e284fdd5c99e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_1bd74b70-c79b-45ea-b691-cb0b3b37bff0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_0d59bb9a-88d4-4d35-96d1-cf3a99e35c7d" xlink:to="loc_us-gaap_LetterOfCreditMember_1bd74b70-c79b-45ea-b691-cb0b3b37bff0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_5bc0dec4-a73f-473e-a589-bffb66011495" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_af00b4cf-7ba1-46f9-b557-750f080d3ebc" xlink:to="loc_us-gaap_VariableRateAxis_5bc0dec4-a73f-473e-a589-bffb66011495" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_5bc0dec4-a73f-473e-a589-bffb66011495_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_5bc0dec4-a73f-473e-a589-bffb66011495" xlink:to="loc_us-gaap_VariableRateDomain_5bc0dec4-a73f-473e-a589-bffb66011495_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_02470f9c-a072-4488-8dcb-ceae2efb4689" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_5bc0dec4-a73f-473e-a589-bffb66011495" xlink:to="loc_us-gaap_VariableRateDomain_02470f9c-a072-4488-8dcb-ceae2efb4689" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_3e78f376-cb21-4e37-acc2-834b1c5f2e1c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_02470f9c-a072-4488-8dcb-ceae2efb4689" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_3e78f376-cb21-4e37-acc2-834b1c5f2e1c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityAxis_3c9f281d-9bcb-4e9b-a174-209ce80ad5c6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_af00b4cf-7ba1-46f9-b557-750f080d3ebc" xlink:to="loc_us-gaap_LineOfCreditFacilityAxis_3c9f281d-9bcb-4e9b-a174-209ce80ad5c6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_3c9f281d-9bcb-4e9b-a174-209ce80ad5c6_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_3c9f281d-9bcb-4e9b-a174-209ce80ad5c6" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_3c9f281d-9bcb-4e9b-a174-209ce80ad5c6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_8334b32b-f772-439d-bfec-e97c992d5002" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_3c9f281d-9bcb-4e9b-a174-209ce80ad5c6" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_8334b32b-f772-439d-bfec-e97c992d5002" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_WellsFargoBarclaysMorganStanleyAndDeutscheBankMember_a2828d61-24e8-4066-b0da-b736e9c31c73" xlink:href="root-20200930.xsd#root_WellsFargoBarclaysMorganStanleyAndDeutscheBankMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_8334b32b-f772-439d-bfec-e97c992d5002" xlink:to="loc_root_WellsFargoBarclaysMorganStanleyAndDeutscheBankMember_a2828d61-24e8-4066-b0da-b736e9c31c73" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/INCOMETAXES" xlink:type="simple" xlink:href="root-20200930.xsd#INCOMETAXES"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/INCOMETAXES" xlink:type="extended" id="i62066b8d784c496cafaf9e6958b2e4ce_INCOMETAXES"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/INCOMETAXESDetails" xlink:type="simple" xlink:href="root-20200930.xsd#INCOMETAXESDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/INCOMETAXESDetails" xlink:type="extended" id="i72566d77d04545b0902ea5f6c713b384_INCOMETAXESDetails"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/CAPITALSTOCK" xlink:type="simple" xlink:href="root-20200930.xsd#CAPITALSTOCK"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/CAPITALSTOCK" xlink:type="extended" id="ia3f7e3c0eb11459cbf891d3cdb9dcaec_CAPITALSTOCK"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/CAPITALSTOCKTables" xlink:type="simple" xlink:href="root-20200930.xsd#CAPITALSTOCKTables"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/CAPITALSTOCKTables" xlink:type="extended" id="if67b618399214b299cf6aa1f2970708d_CAPITALSTOCKTables"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/CAPITALSTOCKDetails" xlink:type="simple" xlink:href="root-20200930.xsd#CAPITALSTOCKDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/CAPITALSTOCKDetails" xlink:type="extended" id="i7996c3e398de4026b61864126e027783_CAPITALSTOCKDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityLineItems_ab850a09-f402-489e-8b6c-e364f787e2cb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesAuthorized_85bc5996-9dc5-43ae-90f8-3354a6889854" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquitySharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_ab850a09-f402-489e-8b6c-e364f787e2cb" xlink:to="loc_us-gaap_TemporaryEquitySharesAuthorized_85bc5996-9dc5-43ae-90f8-3354a6889854" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityParOrStatedValuePerShare_9f5e6654-b17d-432e-8edc-fe55b67fd3b3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquityParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_ab850a09-f402-489e-8b6c-e364f787e2cb" xlink:to="loc_us-gaap_TemporaryEquityParOrStatedValuePerShare_9f5e6654-b17d-432e-8edc-fe55b67fd3b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_1d76a8c6-6061-4bbb-ba35-29fd9adcb51a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_ab850a09-f402-489e-8b6c-e364f787e2cb" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_1d76a8c6-6061-4bbb-ba35-29fd9adcb51a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_adb76ceb-962b-4528-9dd7-75a9bd24a2ab" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_ab850a09-f402-489e-8b6c-e364f787e2cb" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_adb76ceb-962b-4528-9dd7-75a9bd24a2ab" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityByClassOfStockTable_1aadf536-9505-45a6-a0b1-549ea7a88dd6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquityByClassOfStockTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_TemporaryEquityLineItems_ab850a09-f402-489e-8b6c-e364f787e2cb" xlink:to="loc_us-gaap_TemporaryEquityByClassOfStockTable_1aadf536-9505-45a6-a0b1-549ea7a88dd6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_95c28914-533b-41a3-8f52-b5a0f4103226" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_TemporaryEquityByClassOfStockTable_1aadf536-9505-45a6-a0b1-549ea7a88dd6" xlink:to="loc_us-gaap_StatementClassOfStockAxis_95c28914-533b-41a3-8f52-b5a0f4103226" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_95c28914-533b-41a3-8f52-b5a0f4103226_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_95c28914-533b-41a3-8f52-b5a0f4103226" xlink:to="loc_us-gaap_ClassOfStockDomain_95c28914-533b-41a3-8f52-b5a0f4103226_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_e6ffb085-904b-4fe6-873c-d32c083e9846" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_95c28914-533b-41a3-8f52-b5a0f4103226" xlink:to="loc_us-gaap_ClassOfStockDomain_e6ffb085-904b-4fe6-873c-d32c083e9846" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesAPreferredStockMember_0c62c4d1-d462-4cfe-aa7a-1d364a02de79" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesAPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_e6ffb085-904b-4fe6-873c-d32c083e9846" xlink:to="loc_us-gaap_SeriesAPreferredStockMember_0c62c4d1-d462-4cfe-aa7a-1d364a02de79" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_b512cb1f-7fcd-4070-8ad4-49cdaa17b4cc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_e6ffb085-904b-4fe6-873c-d32c083e9846" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_b512cb1f-7fcd-4070-8ad4-49cdaa17b4cc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesCPreferredStockMember_c0f3d5db-40f8-4bd3-b3b3-9ac85d6347ae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesCPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_e6ffb085-904b-4fe6-873c-d32c083e9846" xlink:to="loc_us-gaap_SeriesCPreferredStockMember_c0f3d5db-40f8-4bd3-b3b3-9ac85d6347ae" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesDPreferredStockMember_f425eadd-8dd4-4c85-aeee-a064900158e3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesDPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_e6ffb085-904b-4fe6-873c-d32c083e9846" xlink:to="loc_us-gaap_SeriesDPreferredStockMember_f425eadd-8dd4-4c85-aeee-a064900158e3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesEPreferredStockMember_a7e8dac6-4a71-4401-8d2b-bd3b6f3c0257" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesEPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_e6ffb085-904b-4fe6-873c-d32c083e9846" xlink:to="loc_us-gaap_SeriesEPreferredStockMember_a7e8dac6-4a71-4401-8d2b-bd3b6f3c0257" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/CAPITALSTOCKScheduleofEquityDetails" xlink:type="simple" xlink:href="root-20200930.xsd#CAPITALSTOCKScheduleofEquityDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/CAPITALSTOCKScheduleofEquityDetails" xlink:type="extended" id="i0cddb83698964108b38b76002ac32762_CAPITALSTOCKScheduleofEquityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityLineItems_1aed5a2d-76e5-4caa-8b05-76c3a7c029fa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesAuthorized_a3fe7890-09f4-465f-9407-90b9a446ea48" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquitySharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_1aed5a2d-76e5-4caa-8b05-76c3a7c029fa" xlink:to="loc_us-gaap_TemporaryEquitySharesAuthorized_a3fe7890-09f4-465f-9407-90b9a446ea48" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesIssued_d2fca6d8-4e1f-4ba9-8242-db41e7c75178" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquitySharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_1aed5a2d-76e5-4caa-8b05-76c3a7c029fa" xlink:to="loc_us-gaap_TemporaryEquitySharesIssued_d2fca6d8-4e1f-4ba9-8242-db41e7c75178" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesOutstanding_43590c13-816a-4c1d-8d10-322cb0809b71" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquitySharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_1aed5a2d-76e5-4caa-8b05-76c3a7c029fa" xlink:to="loc_us-gaap_TemporaryEquitySharesOutstanding_43590c13-816a-4c1d-8d10-322cb0809b71" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_c2d29a20-25d2-4033-884d-813327df5829" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_1aed5a2d-76e5-4caa-8b05-76c3a7c029fa" xlink:to="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_c2d29a20-25d2-4033-884d-813327df5829" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_ConvertiblePreferredStockSharesIssuableUponConversion_cb30a7c3-0721-4540-bf0c-9d04019a2e4d" xlink:href="root-20200930.xsd#root_ConvertiblePreferredStockSharesIssuableUponConversion"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_1aed5a2d-76e5-4caa-8b05-76c3a7c029fa" xlink:to="loc_root_ConvertiblePreferredStockSharesIssuableUponConversion_cb30a7c3-0721-4540-bf0c-9d04019a2e4d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityRedemptionPricePerShare_9d735dd3-85f0-4ee9-9f53-55b4a6d96910" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquityRedemptionPricePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_1aed5a2d-76e5-4caa-8b05-76c3a7c029fa" xlink:to="loc_us-gaap_TemporaryEquityRedemptionPricePerShare_9d735dd3-85f0-4ee9-9f53-55b4a6d96910" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityParOrStatedValuePerShare_228e0220-f94a-43e8-920a-f49acc3a9694" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquityParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_1aed5a2d-76e5-4caa-8b05-76c3a7c029fa" xlink:to="loc_us-gaap_TemporaryEquityParOrStatedValuePerShare_228e0220-f94a-43e8-920a-f49acc3a9694" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityLiquidationPreference_539e2360-a52d-41af-ba43-dcbdbfa99c98" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquityLiquidationPreference"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TemporaryEquityLineItems_1aed5a2d-76e5-4caa-8b05-76c3a7c029fa" xlink:to="loc_us-gaap_TemporaryEquityLiquidationPreference_539e2360-a52d-41af-ba43-dcbdbfa99c98" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityByClassOfStockTable_8620fdd0-9077-450a-a9fb-d00798c06f5e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquityByClassOfStockTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_TemporaryEquityLineItems_1aed5a2d-76e5-4caa-8b05-76c3a7c029fa" xlink:to="loc_us-gaap_TemporaryEquityByClassOfStockTable_8620fdd0-9077-450a-a9fb-d00798c06f5e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_b56d6eca-9ba0-406f-addf-eed4344e0ea2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_TemporaryEquityByClassOfStockTable_8620fdd0-9077-450a-a9fb-d00798c06f5e" xlink:to="loc_us-gaap_StatementClassOfStockAxis_b56d6eca-9ba0-406f-addf-eed4344e0ea2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_b56d6eca-9ba0-406f-addf-eed4344e0ea2_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_b56d6eca-9ba0-406f-addf-eed4344e0ea2" xlink:to="loc_us-gaap_ClassOfStockDomain_b56d6eca-9ba0-406f-addf-eed4344e0ea2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_2b37536b-932c-473d-8a69-368797719302" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_b56d6eca-9ba0-406f-addf-eed4344e0ea2" xlink:to="loc_us-gaap_ClassOfStockDomain_2b37536b-932c-473d-8a69-368797719302" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesAPreferredStockMember_6e8c8680-4f74-4d7e-a469-bae45dea2172" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesAPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_2b37536b-932c-473d-8a69-368797719302" xlink:to="loc_us-gaap_SeriesAPreferredStockMember_6e8c8680-4f74-4d7e-a469-bae45dea2172" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_SeriesA1PreferredStockMember_f8435d4d-2ce2-44f8-9277-7a9769813ca3" xlink:href="root-20200930.xsd#root_SeriesA1PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SeriesAPreferredStockMember_6e8c8680-4f74-4d7e-a469-bae45dea2172" xlink:to="loc_root_SeriesA1PreferredStockMember_f8435d4d-2ce2-44f8-9277-7a9769813ca3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_SeriesA2PreferredStockMember_2a644cdd-8fbd-4328-9c47-4fa787b0646f" xlink:href="root-20200930.xsd#root_SeriesA2PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SeriesAPreferredStockMember_6e8c8680-4f74-4d7e-a469-bae45dea2172" xlink:to="loc_root_SeriesA2PreferredStockMember_2a644cdd-8fbd-4328-9c47-4fa787b0646f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_SeriesA3PreferredStockMember_c49266a9-8a00-483b-8357-6639495ce4c6" xlink:href="root-20200930.xsd#root_SeriesA3PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SeriesAPreferredStockMember_6e8c8680-4f74-4d7e-a469-bae45dea2172" xlink:to="loc_root_SeriesA3PreferredStockMember_c49266a9-8a00-483b-8357-6639495ce4c6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_3830d6df-f223-494b-89a9-9a06fd7812ad" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_2b37536b-932c-473d-8a69-368797719302" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_3830d6df-f223-494b-89a9-9a06fd7812ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesCPreferredStockMember_dcf7f65a-9d7e-42f8-b797-ecea8b585aed" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesCPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_2b37536b-932c-473d-8a69-368797719302" xlink:to="loc_us-gaap_SeriesCPreferredStockMember_dcf7f65a-9d7e-42f8-b797-ecea8b585aed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesDPreferredStockMember_5713589c-e18c-424c-9b6f-fd4d1c308b8f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesDPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_2b37536b-932c-473d-8a69-368797719302" xlink:to="loc_us-gaap_SeriesDPreferredStockMember_5713589c-e18c-424c-9b6f-fd4d1c308b8f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesEPreferredStockMember_c20741db-3114-4b74-9ffd-19b1e9170b77" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeriesEPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_2b37536b-932c-473d-8a69-368797719302" xlink:to="loc_us-gaap_SeriesEPreferredStockMember_c20741db-3114-4b74-9ffd-19b1e9170b77" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_SeriesE1PreferredStockMember_620f341c-f927-47b2-be07-f29b205a05f9" xlink:href="root-20200930.xsd#root_SeriesE1PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SeriesEPreferredStockMember_c20741db-3114-4b74-9ffd-19b1e9170b77" xlink:to="loc_root_SeriesE1PreferredStockMember_620f341c-f927-47b2-be07-f29b205a05f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_3eda8421-4b7c-4bd1-a96b-5b553a357cc4" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_TemporaryEquityByClassOfStockTable_8620fdd0-9077-450a-a9fb-d00798c06f5e" xlink:to="loc_srt_RangeAxis_3eda8421-4b7c-4bd1-a96b-5b553a357cc4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_3eda8421-4b7c-4bd1-a96b-5b553a357cc4_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_3eda8421-4b7c-4bd1-a96b-5b553a357cc4" xlink:to="loc_srt_RangeMember_3eda8421-4b7c-4bd1-a96b-5b553a357cc4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_127a782b-5f63-4b2e-86e3-3d800f8bd6b4" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_3eda8421-4b7c-4bd1-a96b-5b553a357cc4" xlink:to="loc_srt_RangeMember_127a782b-5f63-4b2e-86e3-3d800f8bd6b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_2359fc23-af59-42ca-8711-2b4b3e2cbdce" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_127a782b-5f63-4b2e-86e3-3d800f8bd6b4" xlink:to="loc_srt_MinimumMember_2359fc23-af59-42ca-8711-2b4b3e2cbdce" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_72e56757-5489-4e28-ab24-7bdcfc6614db" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_127a782b-5f63-4b2e-86e3-3d800f8bd6b4" xlink:to="loc_srt_MaximumMember_72e56757-5489-4e28-ab24-7bdcfc6614db" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/SHAREBASEDCOMPENSATION" xlink:type="simple" xlink:href="root-20200930.xsd#SHAREBASEDCOMPENSATION"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/SHAREBASEDCOMPENSATION" xlink:type="extended" id="i68e44f6fdd884072a3878139a57c9022_SHAREBASEDCOMPENSATION"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/SHAREBASEDCOMPENSATIONTables" xlink:type="simple" xlink:href="root-20200930.xsd#SHAREBASEDCOMPENSATIONTables"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/SHAREBASEDCOMPENSATIONTables" xlink:type="extended" id="idd8b483bb8834c01a372b3fca6984418_SHAREBASEDCOMPENSATIONTables"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/SHAREBASEDCOMPENSATIONNarrativeDetails" xlink:type="simple" xlink:href="root-20200930.xsd#SHAREBASEDCOMPENSATIONNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/SHAREBASEDCOMPENSATIONNarrativeDetails" xlink:type="extended" id="i144f764382ef440d835cf7fc1e4497f1_SHAREBASEDCOMPENSATIONNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_afafa865-e3a1-4476-b577-7d999530aa5f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_f762b558-f43e-4fbd-9365-16172fb335e3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_afafa865-e3a1-4476-b577-7d999530aa5f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_f762b558-f43e-4fbd-9365-16172fb335e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_327e7f4f-4c53-4ba2-9187-976d33267d9b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_afafa865-e3a1-4476-b577-7d999530aa5f" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_327e7f4f-4c53-4ba2-9187-976d33267d9b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_7dc1d269-f209-4006-ada0-526238239350" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_afafa865-e3a1-4476-b577-7d999530aa5f" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_7dc1d269-f209-4006-ada0-526238239350" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_a2e17c5c-0de1-40d7-97a7-b8d8bcd7edf0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_afafa865-e3a1-4476-b577-7d999530aa5f" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_a2e17c5c-0de1-40d7-97a7-b8d8bcd7edf0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_EarlyExerciseDepositLiability_ae427ecd-766e-4be5-9902-75d4ec365af2" xlink:href="root-20200930.xsd#root_EarlyExerciseDepositLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_afafa865-e3a1-4476-b577-7d999530aa5f" xlink:to="loc_root_EarlyExerciseDepositLiability_ae427ecd-766e-4be5-9902-75d4ec365af2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_92fa527c-4689-473f-a022-537da7f5491a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_afafa865-e3a1-4476-b577-7d999530aa5f" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_92fa527c-4689-473f-a022-537da7f5491a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_2546dede-6443-421e-9c49-c14689796929" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_92fa527c-4689-473f-a022-537da7f5491a" xlink:to="loc_us-gaap_PlanNameAxis_2546dede-6443-421e-9c49-c14689796929" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_2546dede-6443-421e-9c49-c14689796929_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_2546dede-6443-421e-9c49-c14689796929" xlink:to="loc_us-gaap_PlanNameDomain_2546dede-6443-421e-9c49-c14689796929_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_2b93e6bf-1f1f-4e88-865f-b60a0b8a7311" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_2546dede-6443-421e-9c49-c14689796929" xlink:to="loc_us-gaap_PlanNameDomain_2b93e6bf-1f1f-4e88-865f-b60a0b8a7311" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_A2015EquityIncentivePlanMember_b7f6c82b-2ce7-4274-b708-ae5d62c48f14" xlink:href="root-20200930.xsd#root_A2015EquityIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_2b93e6bf-1f1f-4e88-865f-b60a0b8a7311" xlink:to="loc_root_A2015EquityIncentivePlanMember_b7f6c82b-2ce7-4274-b708-ae5d62c48f14" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_1ab739db-ddc1-4fd4-9ece-2458feaa226f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_92fa527c-4689-473f-a022-537da7f5491a" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_1ab739db-ddc1-4fd4-9ece-2458feaa226f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_1ab739db-ddc1-4fd4-9ece-2458feaa226f_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_1ab739db-ddc1-4fd4-9ece-2458feaa226f" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_1ab739db-ddc1-4fd4-9ece-2458feaa226f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_3cda7e9d-5e75-468e-a0d9-47bb8c331743" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_1ab739db-ddc1-4fd4-9ece-2458feaa226f" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_3cda7e9d-5e75-468e-a0d9-47bb8c331743" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesMember_8e9c0a23-3dd4-4edc-8321-0b1ba54063aa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_3cda7e9d-5e75-468e-a0d9-47bb8c331743" xlink:to="loc_us-gaap_OtherLiabilitiesMember_8e9c0a23-3dd4-4edc-8321-0b1ba54063aa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_bd4e44fe-8296-42cd-bb63-8c338e2b484d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_92fa527c-4689-473f-a022-537da7f5491a" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_bd4e44fe-8296-42cd-bb63-8c338e2b484d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_bd4e44fe-8296-42cd-bb63-8c338e2b484d_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_bd4e44fe-8296-42cd-bb63-8c338e2b484d" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_bd4e44fe-8296-42cd-bb63-8c338e2b484d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_1cb6f30b-950b-4c5c-aece-e6c395f1a4e9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_bd4e44fe-8296-42cd-bb63-8c338e2b484d" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_1cb6f30b-950b-4c5c-aece-e6c395f1a4e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_TenderOfferMember_c1cd3d4f-9ab3-4889-a200-cc85fb488c42" xlink:href="root-20200930.xsd#root_TenderOfferMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_1cb6f30b-950b-4c5c-aece-e6c395f1a4e9" xlink:to="loc_root_TenderOfferMember_c1cd3d4f-9ab3-4889-a200-cc85fb488c42" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_b4acb499-aafe-441f-823b-bce771109035" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_92fa527c-4689-473f-a022-537da7f5491a" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_b4acb499-aafe-441f-823b-bce771109035" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_b4acb499-aafe-441f-823b-bce771109035_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_b4acb499-aafe-441f-823b-bce771109035" xlink:to="loc_us-gaap_EquityComponentDomain_b4acb499-aafe-441f-823b-bce771109035_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_433a3cf5-69a7-408f-b052-a29c78b75ef4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_b4acb499-aafe-441f-823b-bce771109035" xlink:to="loc_us-gaap_EquityComponentDomain_433a3cf5-69a7-408f-b052-a29c78b75ef4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_8d1775d7-410e-4920-a7cd-3297c6c3f2e3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_433a3cf5-69a7-408f-b052-a29c78b75ef4" xlink:to="loc_us-gaap_CommonStockMember_8d1775d7-410e-4920-a7cd-3297c6c3f2e3" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/SHAREBASEDCOMPENSATIONOptionActivityDetails" xlink:type="simple" xlink:href="root-20200930.xsd#SHAREBASEDCOMPENSATIONOptionActivityDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/SHAREBASEDCOMPENSATIONOptionActivityDetails" xlink:type="extended" id="ic112856b6a1d42a7b3e5819263980f94_SHAREBASEDCOMPENSATIONOptionActivityDetails"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/SHAREBASEDCOMPENSATIONSharebasedCompensationExpenseDetails" xlink:type="simple" xlink:href="root-20200930.xsd#SHAREBASEDCOMPENSATIONSharebasedCompensationExpenseDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/SHAREBASEDCOMPENSATIONSharebasedCompensationExpenseDetails" xlink:type="extended" id="i791c9b51288a425ba237b3b0dd7b2163_SHAREBASEDCOMPENSATIONSharebasedCompensationExpenseDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_428aa715-3fec-4558-b0be-a2b1491b5573" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_4ac0e494-5a56-4141-8a43-55db985358ab" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_428aa715-3fec-4558-b0be-a2b1491b5573" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_4ac0e494-5a56-4141-8a43-55db985358ab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_809a5371-0c7c-4dfd-b5cf-b737d1d71c26" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_428aa715-3fec-4558-b0be-a2b1491b5573" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_809a5371-0c7c-4dfd-b5cf-b737d1d71c26" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_a111d94f-0b68-4c37-aeec-d24ca2e4de3f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_809a5371-0c7c-4dfd-b5cf-b737d1d71c26" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_a111d94f-0b68-4c37-aeec-d24ca2e4de3f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_a111d94f-0b68-4c37-aeec-d24ca2e4de3f_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_a111d94f-0b68-4c37-aeec-d24ca2e4de3f" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_a111d94f-0b68-4c37-aeec-d24ca2e4de3f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_dda0ea57-5358-474b-a5a6-0ed1e7743abc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_a111d94f-0b68-4c37-aeec-d24ca2e4de3f" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_dda0ea57-5358-474b-a5a6-0ed1e7743abc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_LiabilityForClaimsAndClaimsAdjustmentExpenseMember_bbb3a9ae-b862-4e0d-b37e-d833431d67c0" xlink:href="root-20200930.xsd#root_LiabilityForClaimsAndClaimsAdjustmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_dda0ea57-5358-474b-a5a6-0ed1e7743abc" xlink:to="loc_root_LiabilityForClaimsAndClaimsAdjustmentExpenseMember_bbb3a9ae-b862-4e0d-b37e-d833431d67c0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingAndMarketingExpenseMember_cff5fd74-f238-4de6-acb3-fcc800a1b5ba" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SellingAndMarketingExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_dda0ea57-5358-474b-a5a6-0ed1e7743abc" xlink:to="loc_us-gaap_SellingAndMarketingExpenseMember_cff5fd74-f238-4de6-acb3-fcc800a1b5ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_OtherInsuranceExpenseMember_6499b171-7892-4b8e-9a4a-eaa1f74a3973" xlink:href="root-20200930.xsd#root_OtherInsuranceExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_dda0ea57-5358-474b-a5a6-0ed1e7743abc" xlink:to="loc_root_OtherInsuranceExpenseMember_6499b171-7892-4b8e-9a4a-eaa1f74a3973" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_TechnologyAndDevelopmentExpenseMember_dde3cbcf-4aed-4cee-a0c2-7b7f07270dbf" xlink:href="root-20200930.xsd#root_TechnologyAndDevelopmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_dda0ea57-5358-474b-a5a6-0ed1e7743abc" xlink:to="loc_root_TechnologyAndDevelopmentExpenseMember_dde3cbcf-4aed-4cee-a0c2-7b7f07270dbf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_174bc04b-b73f-4882-988e-270a74ce6713" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_dda0ea57-5358-474b-a5a6-0ed1e7743abc" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_174bc04b-b73f-4882-988e-270a74ce6713" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/RELATEDPARTYLOANS" xlink:type="simple" xlink:href="root-20200930.xsd#RELATEDPARTYLOANS"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/RELATEDPARTYLOANS" xlink:type="extended" id="ie6ce70b89d904a8d9c62e629a8d71e79_RELATEDPARTYLOANS"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/RELATEDPARTYLOANSDetails" xlink:type="simple" xlink:href="root-20200930.xsd#RELATEDPARTYLOANSDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/RELATEDPARTYLOANSDetails" xlink:type="extended" id="iaeabd510b627479eb0519b911b8d9738_RELATEDPARTYLOANSDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_f9bc10c6-3a80-4608-8f4f-466536579c78" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansAndLeasesReceivableRelatedParties_a53a0fe8-1be1-46b4-b4c9-f1a11590691c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoansAndLeasesReceivableRelatedParties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f9bc10c6-3a80-4608-8f4f-466536579c78" xlink:to="loc_us-gaap_LoansAndLeasesReceivableRelatedParties_a53a0fe8-1be1-46b4-b4c9-f1a11590691c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionRate_454394ef-3e9a-4007-a6ce-5a26b5d91676" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f9bc10c6-3a80-4608-8f4f-466536579c78" xlink:to="loc_us-gaap_RelatedPartyTransactionRate_454394ef-3e9a-4007-a6ce-5a26b5d91676" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares_12162a10-e717-497b-bd87-942755b53a5f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f9bc10c6-3a80-4608-8f4f-466536579c78" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares_12162a10-e717-497b-bd87-942755b53a5f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_RelatedPartyTransactionShares_0cf167d0-d099-474b-a0e6-19485274e35f" xlink:href="root-20200930.xsd#root_RelatedPartyTransactionShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f9bc10c6-3a80-4608-8f4f-466536579c78" xlink:to="loc_root_RelatedPartyTransactionShares_0cf167d0-d099-474b-a0e6-19485274e35f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_563b483c-0283-4d2d-8995-ef4dae720505" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f9bc10c6-3a80-4608-8f4f-466536579c78" xlink:to="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_563b483c-0283-4d2d-8995-ef4dae720505" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty_4a336784-28c7-4990-b95c-158096c67a45" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f9bc10c6-3a80-4608-8f4f-466536579c78" xlink:to="loc_us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty_4a336784-28c7-4990-b95c-158096c67a45" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_33c2ce42-d0b6-4d49-9cba-37cf9a4595d3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f9bc10c6-3a80-4608-8f4f-466536579c78" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_33c2ce42-d0b6-4d49-9cba-37cf9a4595d3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_90840983-4a89-46df-bc3c-4f353d6ac382" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f9bc10c6-3a80-4608-8f4f-466536579c78" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_90840983-4a89-46df-bc3c-4f353d6ac382" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_213b8481-be57-4b3a-909a-20ab7fa6e199" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f9bc10c6-3a80-4608-8f4f-466536579c78" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_213b8481-be57-4b3a-909a-20ab7fa6e199" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_9ba87174-5176-4148-9ff5-3e3ddf3f1866" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f9bc10c6-3a80-4608-8f4f-466536579c78" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_9ba87174-5176-4148-9ff5-3e3ddf3f1866" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_f56e3f91-956e-402a-9e14-fbcb608b560c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_9ba87174-5176-4148-9ff5-3e3ddf3f1866" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_f56e3f91-956e-402a-9e14-fbcb608b560c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_f56e3f91-956e-402a-9e14-fbcb608b560c_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_f56e3f91-956e-402a-9e14-fbcb608b560c" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_f56e3f91-956e-402a-9e14-fbcb608b560c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_2825c8c8-7c42-47dd-8b8b-051497976100" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_f56e3f91-956e-402a-9e14-fbcb608b560c" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_2825c8c8-7c42-47dd-8b8b-051497976100" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_b8dc4bcd-104b-4b4e-8c47-2e4cb6984ce5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_2825c8c8-7c42-47dd-8b8b-051497976100" xlink:to="loc_us-gaap_SubsequentEventMember_b8dc4bcd-104b-4b4e-8c47-2e4cb6984ce5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_ad3a4aa5-3c93-4fef-82c0-ae500d5f6379" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_9ba87174-5176-4148-9ff5-3e3ddf3f1866" xlink:to="loc_us-gaap_AwardTypeAxis_ad3a4aa5-3c93-4fef-82c0-ae500d5f6379" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ad3a4aa5-3c93-4fef-82c0-ae500d5f6379_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_ad3a4aa5-3c93-4fef-82c0-ae500d5f6379" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ad3a4aa5-3c93-4fef-82c0-ae500d5f6379_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6d5f6548-6300-4ea6-b136-daff11f103fb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_ad3a4aa5-3c93-4fef-82c0-ae500d5f6379" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6d5f6548-6300-4ea6-b136-daff11f103fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_3416b0b7-9122-4cc7-9567-b63b46dde39f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6d5f6548-6300-4ea6-b136-daff11f103fb" xlink:to="loc_us-gaap_EmployeeStockOptionMember_3416b0b7-9122-4cc7-9567-b63b46dde39f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_725a9c33-d017-4d35-91dd-6d3eef08bc0c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_9ba87174-5176-4148-9ff5-3e3ddf3f1866" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_725a9c33-d017-4d35-91dd-6d3eef08bc0c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_725a9c33-d017-4d35-91dd-6d3eef08bc0c_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_725a9c33-d017-4d35-91dd-6d3eef08bc0c" xlink:to="loc_us-gaap_RelatedPartyDomain_725a9c33-d017-4d35-91dd-6d3eef08bc0c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_699376b0-10ad-4dc6-adb9-a95a088655c2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_725a9c33-d017-4d35-91dd-6d3eef08bc0c" xlink:to="loc_us-gaap_RelatedPartyDomain_699376b0-10ad-4dc6-adb9-a95a088655c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_f1b20f82-d595-4327-a998-89956f8cacd9" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_699376b0-10ad-4dc6-adb9-a95a088655c2" xlink:to="loc_srt_AffiliatedEntityMember_f1b20f82-d595-4327-a998-89956f8cacd9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_8a7f9203-430f-443c-98a2-3c475007917f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_9ba87174-5176-4148-9ff5-3e3ddf3f1866" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_8a7f9203-430f-443c-98a2-3c475007917f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_8a7f9203-430f-443c-98a2-3c475007917f_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_8a7f9203-430f-443c-98a2-3c475007917f" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_8a7f9203-430f-443c-98a2-3c475007917f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_cf5b7f9c-7c03-4cce-8c7a-748ef6ca07ba" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_8a7f9203-430f-443c-98a2-3c475007917f" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_cf5b7f9c-7c03-4cce-8c7a-748ef6ca07ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_LoansReceivableWeightedAverageInterestRateMember_c91141ce-d719-4aca-8e6b-7dd089effeb7" xlink:href="root-20200930.xsd#root_LoansReceivableWeightedAverageInterestRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_cf5b7f9c-7c03-4cce-8c7a-748ef6ca07ba" xlink:to="loc_root_LoansReceivableWeightedAverageInterestRateMember_c91141ce-d719-4aca-8e6b-7dd089effeb7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_UnvestedSharesAcceptedForSettlementOfLoanMember_364de35b-9144-49a4-89e8-acd837c04314" xlink:href="root-20200930.xsd#root_UnvestedSharesAcceptedForSettlementOfLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_cf5b7f9c-7c03-4cce-8c7a-748ef6ca07ba" xlink:to="loc_root_UnvestedSharesAcceptedForSettlementOfLoanMember_364de35b-9144-49a4-89e8-acd837c04314" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_VestedSharesAcceptedForSettlementOfLoanMember_4be753a4-7e01-4478-a624-61e015008ab2" xlink:href="root-20200930.xsd#root_VestedSharesAcceptedForSettlementOfLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_cf5b7f9c-7c03-4cce-8c7a-748ef6ca07ba" xlink:to="loc_root_VestedSharesAcceptedForSettlementOfLoanMember_4be753a4-7e01-4478-a624-61e015008ab2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_ExtinguishmentOfRelatedPartyLoanAndAccruedInterestMember_58e20cf1-3842-4fae-9403-b0d3625aba43" xlink:href="root-20200930.xsd#root_ExtinguishmentOfRelatedPartyLoanAndAccruedInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_cf5b7f9c-7c03-4cce-8c7a-748ef6ca07ba" xlink:to="loc_root_ExtinguishmentOfRelatedPartyLoanAndAccruedInterestMember_58e20cf1-3842-4fae-9403-b0d3625aba43" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_RecognitionOfTreasuryStockMember_8671df7b-a8ad-4d1e-84b0-cd16f6d655eb" xlink:href="root-20200930.xsd#root_RecognitionOfTreasuryStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_cf5b7f9c-7c03-4cce-8c7a-748ef6ca07ba" xlink:to="loc_root_RecognitionOfTreasuryStockMember_8671df7b-a8ad-4d1e-84b0-cd16f6d655eb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_IncrementalShareBasedCompensationCostMember_3a716a66-00fc-484a-b179-c0883dee482f" xlink:href="root-20200930.xsd#root_IncrementalShareBasedCompensationCostMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_cf5b7f9c-7c03-4cce-8c7a-748ef6ca07ba" xlink:to="loc_root_IncrementalShareBasedCompensationCostMember_3a716a66-00fc-484a-b179-c0883dee482f" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/COMMITMENTSANDCONTINGENCIES" xlink:type="simple" xlink:href="root-20200930.xsd#COMMITMENTSANDCONTINGENCIES"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/COMMITMENTSANDCONTINGENCIES" xlink:type="extended" id="i3a08b30c50d24f4584fd1e61f07fbe12_COMMITMENTSANDCONTINGENCIES"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/OTHERCOMPREHENSIVEINCOMEANDACCUMULATEDOTHERCOMPREHENSIVEINCOME" xlink:type="simple" xlink:href="root-20200930.xsd#OTHERCOMPREHENSIVEINCOMEANDACCUMULATEDOTHERCOMPREHENSIVEINCOME"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/OTHERCOMPREHENSIVEINCOMEANDACCUMULATEDOTHERCOMPREHENSIVEINCOME" xlink:type="extended" id="ia08046c8983d4b3d8f7b7c138053d448_OTHERCOMPREHENSIVEINCOMEANDACCUMULATEDOTHERCOMPREHENSIVEINCOME"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/OTHERCOMPREHENSIVEINCOMEANDACCUMULATEDOTHERCOMPREHENSIVEINCOMETables" xlink:type="simple" xlink:href="root-20200930.xsd#OTHERCOMPREHENSIVEINCOMEANDACCUMULATEDOTHERCOMPREHENSIVEINCOMETables"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/OTHERCOMPREHENSIVEINCOMEANDACCUMULATEDOTHERCOMPREHENSIVEINCOMETables" xlink:type="extended" id="ia425c5b4a05b4edd831cf3ee02bbf0af_OTHERCOMPREHENSIVEINCOMEANDACCUMULATEDOTHERCOMPREHENSIVEINCOMETables"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/OTHERCOMPREHENSIVEINCOMEANDACCUMULATEDOTHERCOMPREHENSIVEINCOMEDetails" xlink:type="simple" xlink:href="root-20200930.xsd#OTHERCOMPREHENSIVEINCOMEANDACCUMULATEDOTHERCOMPREHENSIVEINCOMEDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/OTHERCOMPREHENSIVEINCOMEANDACCUMULATEDOTHERCOMPREHENSIVEINCOMEDetails" xlink:type="extended" id="i45d7278c6f6c4f15b5997cd6756c1bce_OTHERCOMPREHENSIVEINCOMEANDACCUMULATEDOTHERCOMPREHENSIVEINCOMEDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_412a88be-92b7-42a3-b1c1-cbb2e0128bdc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_9a2e43b1-8d83-44be-997e-400308de2e04" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_412a88be-92b7-42a3-b1c1-cbb2e0128bdc" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_9a2e43b1-8d83-44be-997e-400308de2e04" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_38e6992b-24bf-43f8-8ed7-985ca8eb03a4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_9a2e43b1-8d83-44be-997e-400308de2e04" xlink:to="loc_us-gaap_StockholdersEquity_38e6992b-24bf-43f8-8ed7-985ca8eb03a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_cca74a8e-5844-4381-97a7-9ea2a17618b2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_9a2e43b1-8d83-44be-997e-400308de2e04" xlink:to="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_cca74a8e-5844-4381-97a7-9ea2a17618b2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_a2fc48ef-5795-4072-be12-6fdee8b142d2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_9a2e43b1-8d83-44be-997e-400308de2e04" xlink:to="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_a2fc48ef-5795-4072-be12-6fdee8b142d2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_e5e6a24c-fede-496d-a31f-5fee4786d9e1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_9a2e43b1-8d83-44be-997e-400308de2e04" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_e5e6a24c-fede-496d-a31f-5fee4786d9e1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_8f1ba67a-0bad-4b24-b2ea-6ec16dfc1dd2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_8488643f-a2c8-4cf9-b333-5c8af0cecea1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_412a88be-92b7-42a3-b1c1-cbb2e0128bdc" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_8488643f-a2c8-4cf9-b333-5c8af0cecea1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_f6f93c40-a4c0-4dd6-a0b9-b1fbdd168369" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_8488643f-a2c8-4cf9-b333-5c8af0cecea1" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_f6f93c40-a4c0-4dd6-a0b9-b1fbdd168369" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_f6f93c40-a4c0-4dd6-a0b9-b1fbdd168369_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_f6f93c40-a4c0-4dd6-a0b9-b1fbdd168369" xlink:to="loc_us-gaap_EquityComponentDomain_f6f93c40-a4c0-4dd6-a0b9-b1fbdd168369_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_ddf9f2a2-7740-40c8-9228-e5347147b032" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_f6f93c40-a4c0-4dd6-a0b9-b1fbdd168369" xlink:to="loc_us-gaap_EquityComponentDomain_ddf9f2a2-7740-40c8-9228-e5347147b032" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_c66c1076-5946-4b79-aaa9-6ba8bb38ea70" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ddf9f2a2-7740-40c8-9228-e5347147b032" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_c66c1076-5946-4b79-aaa9-6ba8bb38ea70" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/LOSSPERSHARE" xlink:type="simple" xlink:href="root-20200930.xsd#LOSSPERSHARE"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/LOSSPERSHARE" xlink:type="extended" id="i1391b4da565c4b13b19ecebe92935cc3_LOSSPERSHARE"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/LOSSPERSHARETables" xlink:type="simple" xlink:href="root-20200930.xsd#LOSSPERSHARETables"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/LOSSPERSHARETables" xlink:type="extended" id="i58ecf13a95ee41678c8e2ab7e55d302a_LOSSPERSHARETables"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/LOSSPERSHAREDetails" xlink:type="simple" xlink:href="root-20200930.xsd#LOSSPERSHAREDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/LOSSPERSHAREDetails" xlink:type="extended" id="i6cf9ff1094244f7fbc6068945c71a442_LOSSPERSHAREDetails"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/LOSSPERSHAREScheduleofAntiDilutiveSecuritiesDetails" xlink:type="simple" xlink:href="root-20200930.xsd#LOSSPERSHAREScheduleofAntiDilutiveSecuritiesDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/LOSSPERSHAREScheduleofAntiDilutiveSecuritiesDetails" xlink:type="extended" id="id0ec5f13ee0e4fbfb980e95318e5e971_LOSSPERSHAREScheduleofAntiDilutiveSecuritiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_67f6454c-ecc4-4375-a47f-4676f2af990a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_d58479a1-439d-4259-b550-b291e144b678" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_67f6454c-ecc4-4375-a47f-4676f2af990a" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_d58479a1-439d-4259-b550-b291e144b678" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_534462df-5314-416f-ac14-eb9ad1615853" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_67f6454c-ecc4-4375-a47f-4676f2af990a" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_534462df-5314-416f-ac14-eb9ad1615853" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_94df7d6e-73bb-4995-be97-ab940c39bbe5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_534462df-5314-416f-ac14-eb9ad1615853" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_94df7d6e-73bb-4995-be97-ab940c39bbe5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_94df7d6e-73bb-4995-be97-ab940c39bbe5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_94df7d6e-73bb-4995-be97-ab940c39bbe5" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_94df7d6e-73bb-4995-be97-ab940c39bbe5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_a83992fb-69a0-432d-a72a-35729659003c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_94df7d6e-73bb-4995-be97-ab940c39bbe5" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_a83992fb-69a0-432d-a72a-35729659003c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_aa99b192-5bc0-4a51-bfd3-84411d7e4906" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_a83992fb-69a0-432d-a72a-35729659003c" xlink:to="loc_us-gaap_EmployeeStockOptionMember_aa99b192-5bc0-4a51-bfd3-84411d7e4906" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RedeemableConvertiblePreferredStockMember_7e74924e-5bdf-4ca3-a5ea-e34b5f06583c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RedeemableConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_a83992fb-69a0-432d-a72a-35729659003c" xlink:to="loc_us-gaap_RedeemableConvertiblePreferredStockMember_7e74924e-5bdf-4ca3-a5ea-e34b5f06583c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantMember_b19ac953-4969-47d9-a607-731d2dcc1409" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_a83992fb-69a0-432d-a72a-35729659003c" xlink:to="loc_us-gaap_WarrantMember_b19ac953-4969-47d9-a607-731d2dcc1409" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/GEOGRAPHICALBREAKDOWNOFDIRECTWRITTENPREMIUM" xlink:type="simple" xlink:href="root-20200930.xsd#GEOGRAPHICALBREAKDOWNOFDIRECTWRITTENPREMIUM"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/GEOGRAPHICALBREAKDOWNOFDIRECTWRITTENPREMIUM" xlink:type="extended" id="i8a39498474074f50bf4e5407c41d448d_GEOGRAPHICALBREAKDOWNOFDIRECTWRITTENPREMIUM"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/GEOGRAPHICALBREAKDOWNOFDIRECTWRITTENPREMIUMTables" xlink:type="simple" xlink:href="root-20200930.xsd#GEOGRAPHICALBREAKDOWNOFDIRECTWRITTENPREMIUMTables"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/GEOGRAPHICALBREAKDOWNOFDIRECTWRITTENPREMIUMTables" xlink:type="extended" id="if901e48549884b8d9a9d52f7cf503fc7_GEOGRAPHICALBREAKDOWNOFDIRECTWRITTENPREMIUMTables"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/GEOGRAPHICALBREAKDOWNOFDIRECTWRITTENPREMIUMDetails" xlink:type="simple" xlink:href="root-20200930.xsd#GEOGRAPHICALBREAKDOWNOFDIRECTWRITTENPREMIUMDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/GEOGRAPHICALBREAKDOWNOFDIRECTWRITTENPREMIUMDetails" xlink:type="extended" id="i288d2feee0ee46eebae0863ccf7adeb4_GEOGRAPHICALBREAKDOWNOFDIRECTWRITTENPREMIUMDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectsOfReinsuranceLineItems_4b7dbabe-5cf3-4b94-8bfd-22cdac9446e5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EffectsOfReinsuranceLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectPremiumsWritten_e5d956f8-50af-4f8c-8355-84a65318143e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DirectPremiumsWritten"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EffectsOfReinsuranceLineItems_4b7dbabe-5cf3-4b94-8bfd-22cdac9446e5" xlink:to="loc_us-gaap_DirectPremiumsWritten_e5d956f8-50af-4f8c-8355-84a65318143e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_25c4de7d-8368-4ac5-a43f-d7ac675bada4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EffectsOfReinsuranceLineItems_4b7dbabe-5cf3-4b94-8bfd-22cdac9446e5" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_25c4de7d-8368-4ac5-a43f-d7ac675bada4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectsOfReinsuranceTable_e60874a6-bfa9-458a-b22e-0c6442c05ba5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EffectsOfReinsuranceTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EffectsOfReinsuranceLineItems_4b7dbabe-5cf3-4b94-8bfd-22cdac9446e5" xlink:to="loc_us-gaap_EffectsOfReinsuranceTable_e60874a6-bfa9-458a-b22e-0c6442c05ba5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_ba7d71b0-501a-4a40-ad49-7c44f86720b5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_EffectsOfReinsuranceTable_e60874a6-bfa9-458a-b22e-0c6442c05ba5" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_ba7d71b0-501a-4a40-ad49-7c44f86720b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_ba7d71b0-501a-4a40-ad49-7c44f86720b5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_ba7d71b0-501a-4a40-ad49-7c44f86720b5" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_ba7d71b0-501a-4a40-ad49-7c44f86720b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_dc2b2b4f-e9b1-45fb-af58-4edf396a5495" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_ba7d71b0-501a-4a40-ad49-7c44f86720b5" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_dc2b2b4f-e9b1-45fb-af58-4edf396a5495" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicConcentrationRiskMember_959ebb14-779a-4a73-abc1-6370b7cf3a40" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeographicConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_dc2b2b4f-e9b1-45fb-af58-4edf396a5495" xlink:to="loc_us-gaap_GeographicConcentrationRiskMember_959ebb14-779a-4a73-abc1-6370b7cf3a40" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_f13bb0dd-6e52-49b0-913a-be441a09c226" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_EffectsOfReinsuranceTable_e60874a6-bfa9-458a-b22e-0c6442c05ba5" xlink:to="loc_srt_StatementGeographicalAxis_f13bb0dd-6e52-49b0-913a-be441a09c226" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_f13bb0dd-6e52-49b0-913a-be441a09c226_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_f13bb0dd-6e52-49b0-913a-be441a09c226" xlink:to="loc_srt_SegmentGeographicalDomain_f13bb0dd-6e52-49b0-913a-be441a09c226_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_4f5d8529-311d-4576-ba01-a0e2244ceda4" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_f13bb0dd-6e52-49b0-913a-be441a09c226" xlink:to="loc_srt_SegmentGeographicalDomain_4f5d8529-311d-4576-ba01-a0e2244ceda4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_TX_69e8c87a-85c3-4970-820f-0f004f7c5060" xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_TX"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_4f5d8529-311d-4576-ba01-a0e2244ceda4" xlink:to="loc_stpr_TX_69e8c87a-85c3-4970-820f-0f004f7c5060" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_GA_b701566a-296e-43d3-bfc4-fab1d4e42285" xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_GA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_4f5d8529-311d-4576-ba01-a0e2244ceda4" xlink:to="loc_stpr_GA_b701566a-296e-43d3-bfc4-fab1d4e42285" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_KY_769c6f86-3ea6-4cba-8373-53c87c21d24a" xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_KY"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_4f5d8529-311d-4576-ba01-a0e2244ceda4" xlink:to="loc_stpr_KY_769c6f86-3ea6-4cba-8373-53c87c21d24a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_PA_a394079b-1d53-41ce-ab20-d4cfe6ba4345" xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_PA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_4f5d8529-311d-4576-ba01-a0e2244ceda4" xlink:to="loc_stpr_PA_a394079b-1d53-41ce-ab20-d4cfe6ba4345" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_AZ_4d6357b2-4258-4b4a-b748-260873f66f1d" xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_AZ"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_4f5d8529-311d-4576-ba01-a0e2244ceda4" xlink:to="loc_stpr_AZ_4d6357b2-4258-4b4a-b748-260873f66f1d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_MO_eaebc74d-2d4d-4983-bc0c-d09e98035800" xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_MO"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_4f5d8529-311d-4576-ba01-a0e2244ceda4" xlink:to="loc_stpr_MO_eaebc74d-2d4d-4983-bc0c-d09e98035800" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_LA_e7d458b1-2464-4f3e-8a4b-8bf5ae4798ed" xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_LA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_4f5d8529-311d-4576-ba01-a0e2244ceda4" xlink:to="loc_stpr_LA_e7d458b1-2464-4f3e-8a4b-8bf5ae4798ed" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_UT_db6b998f-cc2e-4d2d-ad27-e26a99ce1d9e" xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_UT"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_4f5d8529-311d-4576-ba01-a0e2244ceda4" xlink:to="loc_stpr_UT_db6b998f-cc2e-4d2d-ad27-e26a99ce1d9e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_OH_7ad9a1f8-e90b-48f5-a7b5-096440d788a5" xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_OH"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_4f5d8529-311d-4576-ba01-a0e2244ceda4" xlink:to="loc_stpr_OH_7ad9a1f8-e90b-48f5-a7b5-096440d788a5" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_OR_7392eea7-5a08-4452-9b86-7b18cc92dec7" xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_OR"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_4f5d8529-311d-4576-ba01-a0e2244ceda4" xlink:to="loc_stpr_OR_7392eea7-5a08-4452-9b86-7b18cc92dec7" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_AllOtherStatesMember_57a2440f-efc7-4fb5-885c-c00ce1ec166b" xlink:href="root-20200930.xsd#root_AllOtherStatesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_4f5d8529-311d-4576-ba01-a0e2244ceda4" xlink:to="loc_root_AllOtherStatesMember_57a2440f-efc7-4fb5-885c-c00ce1ec166b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_08c78789-ea02-4d8c-941a-ad2497ac3ee8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_EffectsOfReinsuranceTable_e60874a6-bfa9-458a-b22e-0c6442c05ba5" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_08c78789-ea02-4d8c-941a-ad2497ac3ee8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_08c78789-ea02-4d8c-941a-ad2497ac3ee8_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_08c78789-ea02-4d8c-941a-ad2497ac3ee8" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_08c78789-ea02-4d8c-941a-ad2497ac3ee8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_613c7ae1-aadf-4c2f-9271-6e099357a83e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_08c78789-ea02-4d8c-941a-ad2497ac3ee8" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_613c7ae1-aadf-4c2f-9271-6e099357a83e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_DirectWrittenPremiumsMember_46e5af15-acd3-44f7-94f4-d864dae140be" xlink:href="root-20200930.xsd#root_DirectWrittenPremiumsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_613c7ae1-aadf-4c2f-9271-6e099357a83e" xlink:to="loc_root_DirectWrittenPremiumsMember_46e5af15-acd3-44f7-94f4-d864dae140be" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.joinroot.com/role/SUBSEQUENTEVENTS" xlink:type="simple" xlink:href="root-20200930.xsd#SUBSEQUENTEVENTS"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/SUBSEQUENTEVENTS" xlink:type="extended" id="ied9ac5ab0c7e4165bf2629de510a9ef0_SUBSEQUENTEVENTS"/>
  <link:roleRef roleURI="http://www.joinroot.com/role/SUBSEQUENTEVENTSDetails" xlink:type="simple" xlink:href="root-20200930.xsd#SUBSEQUENTEVENTSDetails"/>
  <link:definitionLink xlink:role="http://www.joinroot.com/role/SUBSEQUENTEVENTSDetails" xlink:type="extended" id="i85cb1538f6db4d20a69dc10b34075cb6_SUBSEQUENTEVENTSDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_28dc40a5-297b-470a-85ed-7d09ba494d67" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_28dc40a5-297b-470a-85ed-7d09ba494d67" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesAuthorized_2d53f471-9540-4b8a-b93a-e5913be920b5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquitySharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_us-gaap_TemporaryEquitySharesAuthorized_2d53f471-9540-4b8a-b93a-e5913be920b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityParOrStatedValuePerShare_2f502c4f-cdbb-4132-8ad2-77849775cc19" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TemporaryEquityParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_us-gaap_TemporaryEquityParOrStatedValuePerShare_2f502c4f-cdbb-4132-8ad2-77849775cc19" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_f378d8c1-e350-4fd6-a1a0-d40553d784e9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_f378d8c1-e350-4fd6-a1a0-d40553d784e9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_CommonStockVotingRightsVotes_9eba7d8e-15c1-424c-abad-ffed957990b1" xlink:href="root-20200930.xsd#root_CommonStockVotingRightsVotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_root_CommonStockVotingRightsVotes_9eba7d8e-15c1-424c-abad-ffed957990b1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_8829a8de-ea5c-4db5-bbbb-063df2a9c35d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_8829a8de-ea5c-4db5-bbbb-063df2a9c35d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockPricePerShare_649c97a5-e917-441c-9b61-2633ece8dff0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SaleOfStockPricePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_us-gaap_SaleOfStockPricePerShare_649c97a5-e917-441c-9b61-2633ece8dff0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOrSaleOfEquity_1951f39f-944a-417f-b37d-8dbbcc80b373" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromIssuanceOrSaleOfEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_us-gaap_ProceedsFromIssuanceOrSaleOfEquity_1951f39f-944a-417f-b37d-8dbbcc80b373" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts_9fa9e64a-fc59-4dfd-bdb4-cbc78238e6a4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsOfStockIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts_9fa9e64a-fc59-4dfd-bdb4-cbc78238e6a4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_ClassOfWarrantOrRightWarrantsExercised_6bc73a3c-34f0-48c0-acd9-5b34e8203ac0" xlink:href="root-20200930.xsd#root_ClassOfWarrantOrRightWarrantsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_root_ClassOfWarrantOrRightWarrantsExercised_6bc73a3c-34f0-48c0-acd9-5b34e8203ac0" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_ClassOfWarrantOrRightInterestExpenseRecognized_974a04e7-78bc-4298-b60a-b364a49eeb21" xlink:href="root-20200930.xsd#root_ClassOfWarrantOrRightInterestExpenseRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_root_ClassOfWarrantOrRightInterestExpenseRecognized_974a04e7-78bc-4298-b60a-b364a49eeb21" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_9f46df81-bab0-4704-b3a3-bbb2d6d6e4de" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_9f46df81-bab0-4704-b3a3-bbb2d6d6e4de" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorizedAnnualIncreasePercentageOfOutstandingShares_bd7cb5c6-6055-4e7a-abf7-949f5f2640ef" xlink:href="root-20200930.xsd#root_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorizedAnnualIncreasePercentageOfOutstandingShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_root_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorizedAnnualIncreasePercentageOfOutstandingShares_bd7cb5c6-6055-4e7a-abf7-949f5f2640ef" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_ShareBasedCompensationByShareBasedPaymentArrangementMaximumSharesIssuedPursuantToExercisedOptions_19abc50e-d7ea-4575-b284-c54554a08e0b" xlink:href="root-20200930.xsd#root_ShareBasedCompensationByShareBasedPaymentArrangementMaximumSharesIssuedPursuantToExercisedOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_root_ShareBasedCompensationByShareBasedPaymentArrangementMaximumSharesIssuedPursuantToExercisedOptions_19abc50e-d7ea-4575-b284-c54554a08e0b" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorizedAnnualIncreaseOutstandingShares_2f07c376-2058-41ea-b627-bdddfcdfa495" xlink:href="root-20200930.xsd#root_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorizedAnnualIncreaseOutstandingShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_root_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorizedAnnualIncreaseOutstandingShares_2f07c376-2058-41ea-b627-bdddfcdfa495" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_f87b1a73-fda4-4bab-819e-a7441e27ed95" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_f87b1a73-fda4-4bab-819e-a7441e27ed95" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndCashEquivalentsAndInvestmentIncome_0b5a4aad-5b42-4950-b23b-19d0ae3efcc9" xlink:href="root-20200930.xsd#root_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndCashEquivalentsAndInvestmentIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_root_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndCashEquivalentsAndInvestmentIncome_0b5a4aad-5b42-4950-b23b-19d0ae3efcc9" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets_70e53839-2a03-47e8-8efc-775afe8dc64e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets_70e53839-2a03-47e8-8efc-775afe8dc64e" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_NumberOfStatesInWhichEntityOperatesAutoPoliciesWritten_70421e0d-7492-4972-8b55-f4b48ef261c1" xlink:href="root-20200930.xsd#root_NumberOfStatesInWhichEntityOperatesAutoPoliciesWritten"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_root_NumberOfStatesInWhichEntityOperatesAutoPoliciesWritten_70421e0d-7492-4972-8b55-f4b48ef261c1" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_5bba86ed-a154-47bf-a2dc-27e292071cd2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_c975d01c-f3e0-4596-a6c0-77749d48e13d" xlink:to="loc_us-gaap_SubsequentEventTable_5bba86ed-a154-47bf-a2dc-27e292071cd2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_b2bc5edd-7a6b-4278-8d44-97c199f3c99a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_5bba86ed-a154-47bf-a2dc-27e292071cd2" xlink:to="loc_us-gaap_StatementClassOfStockAxis_b2bc5edd-7a6b-4278-8d44-97c199f3c99a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_b2bc5edd-7a6b-4278-8d44-97c199f3c99a_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_b2bc5edd-7a6b-4278-8d44-97c199f3c99a" xlink:to="loc_us-gaap_ClassOfStockDomain_b2bc5edd-7a6b-4278-8d44-97c199f3c99a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_ab9cc430-f1de-4f74-95bc-a4db8b1ee2a4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_b2bc5edd-7a6b-4278-8d44-97c199f3c99a" xlink:to="loc_us-gaap_ClassOfStockDomain_ab9cc430-f1de-4f74-95bc-a4db8b1ee2a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_7c9e6df1-8932-4f0c-b2ad-bfbfa72d12c1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_ab9cc430-f1de-4f74-95bc-a4db8b1ee2a4" xlink:to="loc_us-gaap_CommonClassAMember_7c9e6df1-8932-4f0c-b2ad-bfbfa72d12c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_500985ea-b63a-4074-ba83-90451f716bbb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_ab9cc430-f1de-4f74-95bc-a4db8b1ee2a4" xlink:to="loc_us-gaap_CommonClassBMember_500985ea-b63a-4074-ba83-90451f716bbb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_d85afa47-e3bf-453b-91ef-36754d892c8c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_5bba86ed-a154-47bf-a2dc-27e292071cd2" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_d85afa47-e3bf-453b-91ef-36754d892c8c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_d85afa47-e3bf-453b-91ef-36754d892c8c_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_d85afa47-e3bf-453b-91ef-36754d892c8c" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_d85afa47-e3bf-453b-91ef-36754d892c8c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_cd209a43-f6da-49fe-a82c-051d55e92b00" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_d85afa47-e3bf-453b-91ef-36754d892c8c" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_cd209a43-f6da-49fe-a82c-051d55e92b00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_9d6f5f82-30d1-480c-8e16-ca9e7b822db2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_cd209a43-f6da-49fe-a82c-051d55e92b00" xlink:to="loc_us-gaap_SubsequentEventMember_9d6f5f82-30d1-480c-8e16-ca9e7b822db2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_3aceb204-6aaa-4f4b-83b3-2fd2827e2a49" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_5bba86ed-a154-47bf-a2dc-27e292071cd2" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_3aceb204-6aaa-4f4b-83b3-2fd2827e2a49" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_3aceb204-6aaa-4f4b-83b3-2fd2827e2a49_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_3aceb204-6aaa-4f4b-83b3-2fd2827e2a49" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_3aceb204-6aaa-4f4b-83b3-2fd2827e2a49_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_9949b500-6000-46e2-8836-946f0855e9bd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_3aceb204-6aaa-4f4b-83b3-2fd2827e2a49" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_9949b500-6000-46e2-8836-946f0855e9bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IPOMember_92400eec-142b-4fe9-845e-9e661818bad3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IPOMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_9949b500-6000-46e2-8836-946f0855e9bd" xlink:to="loc_us-gaap_IPOMember_92400eec-142b-4fe9-845e-9e661818bad3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrivatePlacementMember_7350cfeb-2be0-4f19-9681-fb695c4f5216" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PrivatePlacementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_9949b500-6000-46e2-8836-946f0855e9bd" xlink:to="loc_us-gaap_PrivatePlacementMember_7350cfeb-2be0-4f19-9681-fb695c4f5216" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_6b628c93-fd85-4ad6-b4b4-7694e75e0d35" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_5bba86ed-a154-47bf-a2dc-27e292071cd2" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_6b628c93-fd85-4ad6-b4b4-7694e75e0d35" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_6b628c93-fd85-4ad6-b4b4-7694e75e0d35_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6b628c93-fd85-4ad6-b4b4-7694e75e0d35" xlink:to="loc_us-gaap_EquityComponentDomain_6b628c93-fd85-4ad6-b4b4-7694e75e0d35_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_cf67652b-dda7-4bb2-9cff-559e25f4373c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6b628c93-fd85-4ad6-b4b4-7694e75e0d35" xlink:to="loc_us-gaap_EquityComponentDomain_cf67652b-dda7-4bb2-9cff-559e25f4373c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_251187b1-65e4-4c65-8291-e689471ebe98" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_cf67652b-dda7-4bb2-9cff-559e25f4373c" xlink:to="loc_us-gaap_CommonStockMember_251187b1-65e4-4c65-8291-e689471ebe98" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_23579757-9d81-4465-8b52-492eae9fcfba" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_5bba86ed-a154-47bf-a2dc-27e292071cd2" xlink:to="loc_us-gaap_PlanNameAxis_23579757-9d81-4465-8b52-492eae9fcfba" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_23579757-9d81-4465-8b52-492eae9fcfba_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_23579757-9d81-4465-8b52-492eae9fcfba" xlink:to="loc_us-gaap_PlanNameDomain_23579757-9d81-4465-8b52-492eae9fcfba_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_8b4df450-10d7-407e-bc0b-5ad3b849e8bd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_23579757-9d81-4465-8b52-492eae9fcfba" xlink:to="loc_us-gaap_PlanNameDomain_8b4df450-10d7-407e-bc0b-5ad3b849e8bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_A2020EquityIncentivePlanMember_d0aae6e7-a382-4508-9195-70d39a2150c4" xlink:href="root-20200930.xsd#root_A2020EquityIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_8b4df450-10d7-407e-bc0b-5ad3b849e8bd" xlink:to="loc_root_A2020EquityIncentivePlanMember_d0aae6e7-a382-4508-9195-70d39a2150c4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_A2020EmployeeStockPurchasePlanMember_a28a278b-4a9c-4460-abcc-56117f4cb8f1" xlink:href="root-20200930.xsd#root_A2020EmployeeStockPurchasePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_8b4df450-10d7-407e-bc0b-5ad3b849e8bd" xlink:to="loc_root_A2020EmployeeStockPurchasePlanMember_a28a278b-4a9c-4460-abcc-56117f4cb8f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_86b6a361-724f-46f1-818a-8676835516ec" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_5bba86ed-a154-47bf-a2dc-27e292071cd2" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_86b6a361-724f-46f1-818a-8676835516ec" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_86b6a361-724f-46f1-818a-8676835516ec_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_86b6a361-724f-46f1-818a-8676835516ec" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_86b6a361-724f-46f1-818a-8676835516ec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_fb512a2a-6896-4dee-aeed-a150ef6e6a31" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_86b6a361-724f-46f1-818a-8676835516ec" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_fb512a2a-6896-4dee-aeed-a150ef6e6a31" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_root_ShellInsuranceCompanyMember_b723538e-4f7c-460f-a508-34d40e194184" xlink:href="root-20200930.xsd#root_ShellInsuranceCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_fb512a2a-6896-4dee-aeed-a150ef6e6a31" xlink:to="loc_root_ShellInsuranceCompanyMember_b723538e-4f7c-460f-a508-34d40e194184" xlink:type="arc" order="0"/>
  </link:definitionLink>
</link:linkbase>
