word-forming element meaning "before," from Old French pre- and Medieval Latin pre-, both from Latin prae (adverb and preposition) "before in time or place," from PIE *peri- (source also of Oscan prai, Umbrian pre, Sanskrit pare "thereupon," Greek parai "at," Gaulish are- "at, before," Lithuanian prie "at," Old Church Slavonic pri "at," Gothic faura, Old English fore "before"), extended form of root *per- (1) "forward," hence "beyond, in front of, before."
The Latin word was active in forming verbs. Also see prae-. Sometimes in Middle English muddled with words in pro- or per-.
1620s, "act of selecting," from Latin selectionem (nominative selectio) "a choosing out, choice, selection," noun of action from past-participle stem of seligere "choose out, single out, select; separate, cull" (see select (adj.)). Meaning "thing selected" is from 1805. Biological sense is from 1837; applied to actions of breeders (methodical selection), hence its use by Darwin (natural selection; 1857). French sélection is a 19c. borrowing from English.