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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:01a01fdd-9db4-75b1-bd53-07cc0ddf7051,g:0f64769a-c0cd-4075-bbf1-925c8271ec10-->
<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://better.com/role/Cover" xlink:type="simple" xlink:href="betr-20260827.xsd#Cover"/>
  <link:definitionLink xlink:role="http://better.com/role/Cover" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_01a01fdd-9db4-7655-8ee6-06b788b71818" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentInformationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_DocumentInformationTable_01a01fdd-9db4-7655-8ee6-06b788b71818" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_01a01fdd-9db4-7515-8aa2-81b562be4d40" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_01a01fdd-9db4-7655-8ee6-06b788b71818" xlink:to="loc_us-gaap_StatementClassOfStockAxis_01a01fdd-9db4-7515-8aa2-81b562be4d40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a01fdd-9db4-7515-8aa2-81b562be4d40_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_01a01fdd-9db4-7515-8aa2-81b562be4d40" xlink:to="loc_us-gaap_ClassOfStockDomain_01a01fdd-9db4-7515-8aa2-81b562be4d40_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a01fdd-9db4-7957-b2d1-0cae40e53086" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_01a01fdd-9db4-7515-8aa2-81b562be4d40" xlink:to="loc_us-gaap_ClassOfStockDomain_01a01fdd-9db4-7957-b2d1-0cae40e53086" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_01a01fdd-9db4-7b83-a136-0a5d1f956b1f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a01fdd-9db4-7957-b2d1-0cae40e53086" xlink:to="loc_us-gaap_CommonClassAMember_01a01fdd-9db4-7b83-a136-0a5d1f956b1f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantMember_01a01fdd-9db4-73ad-95a2-051515b13897" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a01fdd-9db4-7957-b2d1-0cae40e53086" xlink:to="loc_us-gaap_WarrantMember_01a01fdd-9db4-73ad-95a2-051515b13897" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_01a01fdd-9db4-78e9-8c48-7a879ffcfe09" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_DocumentType_01a01fdd-9db4-78e9-8c48-7a879ffcfe09" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_01a01fdd-9db4-724c-a69f-cd8b84d88a13" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_DocumentPeriodEndDate_01a01fdd-9db4-724c-a69f-cd8b84d88a13" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_01a01fdd-9db4-7e7e-819f-8a43bc2ea8b3" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_EntityRegistrantName_01a01fdd-9db4-7e7e-819f-8a43bc2ea8b3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_01a01fdd-9db4-7897-a20d-5f93ce50157b" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_EntityIncorporationStateCountryCode_01a01fdd-9db4-7897-a20d-5f93ce50157b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_01a01fdd-9db4-7ee4-be0a-cf3700e11724" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_EntityFileNumber_01a01fdd-9db4-7ee4-be0a-cf3700e11724" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_01a01fdd-9db4-7d09-bf41-4312ceb58558" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_EntityTaxIdentificationNumber_01a01fdd-9db4-7d09-bf41-4312ceb58558" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_01a01fdd-9db4-7529-ad65-e51b7a7bfcc6" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_EntityAddressAddressLine1_01a01fdd-9db4-7529-ad65-e51b7a7bfcc6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine2_01a01fdd-9db4-78f7-b507-7bcbc3c2906e" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_EntityAddressAddressLine2_01a01fdd-9db4-78f7-b507-7bcbc3c2906e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_01a01fdd-9db4-7718-b48e-594712bf3fcc" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_EntityAddressCityOrTown_01a01fdd-9db4-7718-b48e-594712bf3fcc" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_01a01fdd-9db4-7c89-829e-98589a500c44" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_EntityAddressStateOrProvince_01a01fdd-9db4-7c89-829e-98589a500c44" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_01a01fdd-9db4-74ff-a9dd-544ad472b880" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_EntityAddressPostalZipCode_01a01fdd-9db4-74ff-a9dd-544ad472b880" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_01a01fdd-9db4-74ed-9633-41e792d18173" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_CityAreaCode_01a01fdd-9db4-74ed-9633-41e792d18173" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_01a01fdd-9db4-7d06-b84e-ef81cc74fee8" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_LocalPhoneNumber_01a01fdd-9db4-7d06-b84e-ef81cc74fee8" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_01a01fdd-9db4-754e-87f8-212798c53aa6" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_WrittenCommunications_01a01fdd-9db4-754e-87f8-212798c53aa6" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_01a01fdd-9db4-7abe-9472-c07089482532" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_SolicitingMaterial_01a01fdd-9db4-7abe-9472-c07089482532" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_01a01fdd-9db4-7340-a57a-5f8b049f3b60" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_PreCommencementTenderOffer_01a01fdd-9db4-7340-a57a-5f8b049f3b60" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_01a01fdd-9db4-729a-bc39-7dd14ef83e3c" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_01a01fdd-9db4-729a-bc39-7dd14ef83e3c" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_01a01fdd-9db4-7129-8e7c-b2ce0567cb63" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_Security12bTitle_01a01fdd-9db4-7129-8e7c-b2ce0567cb63" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_01a01fdd-9db4-7811-b7af-1c100722cd74" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_TradingSymbol_01a01fdd-9db4-7811-b7af-1c100722cd74" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_01a01fdd-9db4-7a59-8c7c-b0a50b59e115" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_SecurityExchangeName_01a01fdd-9db4-7a59-8c7c-b0a50b59e115" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_01a01fdd-9db4-7ee4-9f49-d118273708f5" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_EntityEmergingGrowthCompany_01a01fdd-9db4-7ee4-9f49-d118273708f5" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityExTransitionPeriod_01a01fdd-9db4-7d46-ba73-14b2c74abdcb" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityExTransitionPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_EntityExTransitionPeriod_01a01fdd-9db4-7d46-ba73-14b2c74abdcb" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_01a01fdd-9db4-7df3-9a71-5e95b57b4556" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_EntityCentralIndexKey_01a01fdd-9db4-7df3-9a71-5e95b57b4556" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_01a01fdd-9db4-7a3e-b71b-ede7348dd0fc" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a01fdd-9db4-7009-8059-21fbaae7b98b" xlink:to="loc_dei_AmendmentFlag_01a01fdd-9db4-7a3e-b71b-ede7348dd0fc" xlink:type="arc" order="23"/>
  </link:definitionLink>
</link:linkbase>
