Sponsor comes from Latin spondēre ('to pledge solemnly'), rooted in PIE *spend- ('to pour a libation'). The same root gives us spouse, respond, and despondent — all words about making or breaking promises.
A person or organisation that provides funds for an event or activity; one who takes responsibility for another person.
From Latin sponsor meaning 'one who gives a guarantee, a surety', from spondēre meaning 'to promise solemnly, to pledge'. The Proto-Indo-European root *spend- meant 'to make an offering, to perform a ritual, to pour a libation'. The original sponsor was not a corporate backer but a sacred guarantor — one who sealed a promise by pouring wine to the
Sponsor, spouse, respond, and despondent all come from Latin spondēre ('to pledge'). A spouse is someone pledged in marriage. To respond is to pledge back. To be despondent is to have given up your pledge — literally de-spondēre, to un-promise. And the original sponsors poured wine on altars to seal their oaths before the gods.