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-.
c. 1200, terme "limit in time, set or appointed period," from Old French terme "limit of time or place, date, appointed time, duration" (11c.), from Latin terminus "end, boundary line," in Medieval Latin "expression, definition," related to termen "boundary, end" (see terminus). Old English had termen "term, end," from Latin. Sense of "period of time during which something happens" first recorded c. 1300, especially of a school or law court session (mid-15c.).
The meaning "word or phrase used in a limited or precise sense" is first recorded late 14c., from Medieval Latin use of terminus to render Greek horos "boundary," employed in mathematics and logic. Hence in terms of "in the language or phraseology peculiar to." Meaning "completion of the period of pregnancy" is from 1844. Term-paper in U.S. educational sense is recorded from 1931.