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-.
"grinding tooth, back-tooth," mid-14c., from Latin molaris dens "grinding tooth," from mola "millstone," from PIE root *mele- "to crush, grind." As an adjective, "grinding, crushing," as distinguished from "cutting" or "piercing," from 1620s. In Old English they were cweornteð "quern-teeth."
<a href="https://www.etymonline.com/word/premolar">Etymology of premolar by etymonline</a>
Harper, D. (n.d.). Etymology of premolar. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/premolar