'endowment-friendly' originates from modern English, specifically the combination of 'endowment' and 'friendly', where 'endowment' meant 'a fund or gift (especially for an institution)' and 'friendly' meant 'showing favor or support'.

'endowment' changed from Middle English 'endowement' (from verb 'endowen') and Old French 'endouer' (to give a dowry), ultimately from Latin 'dotare' ('to give as a dowry'); 'friendly' developed from Old English 'freondlic' (from 'freond' meaning 'friend') and evolved into modern 'friendly'.

Initially the roots related to giving a dowry and to being 'friend-like'; over time 'endowment' shifted to mean an institutional fund, so the combined adjective came to mean 'supportive or favorable to institutional endowments'.