endow v.

word-forming element meaning "in; into," from French and Old French en-, from Latin in- "in, into" (from PIE root *en "in"). Typically assimilated before -p-, -b-, -m-, -l-, and -r-. Latin in- became en- in French, Spanish, Portuguese, but remained in- in Italian.

Also used with native and imported elements to form verbs from nouns and adjectives, with a sense "put in or on" (encircle), also "cause to be, make into" (endear), and used as an intensive (enclose). Spelling variants in French that were brought over into Middle English account for parallels such as ensure/insure, and most en- words in English had at one time or another a variant in in-, and vice versa.

*dō-, Proto-Indo-European root meaning "to give."

It forms all or part of: add; anecdote; antidote; betray; condone; dacha; dado; data; date (n.1) "time;" dative; deodand; die (n.); donation; donative; donor; Dorian; Dorothy; dose; dowager; dower; dowry; edition; endow; Eudora; fedora; Isidore; mandate; Pandora; pardon; perdition; Polydorus; render; rent (n.1) "payment for use of property;" sacerdotal; samizdat; surrender; Theodore; Theodosia; tradition; traitor; treason; vend.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit dadati "gives," danam "offering, present;" Old Persian dadatuv "let him give;" Greek didomi, didonai, "to give, offer," dōron "gift;" Latin dare "to give, grant, offer," donum "gift;" Armenian tam "to give;" Old Church Slavonic dati "give," dani "tribute;" Lithuanian duoti "to give," duonis "gift;" Old Irish dan "gift, endowment, talent," Welsh dawn "gift."