What is "prae-"

Pre- \Pre-\ [L. prae, adv. & prep., before, akin to pro, and to E. for, prep.: cf. F. pr['e]-. See Pro-, and cf. Prior.] A prefix denoting priority (of time, place, or rank); as, precede, to go before; precursor, a forerunner; prefix, to fix or place before; pre["e]minent eminent before or above others. Pre- is sometimes used intensively, as in prepotent, very potent. [Written also pr[ae]-.]

word-forming element meaning "before," from Latin prae (adv.) "before," from PIE *prai-, *prei-, from root *per- (1) "forward, through" (see per; also see pre-). Reduced to pre- in Medieval Latin. According to OED the full form prae- in Modern English appears "usually only in words that are still regarded as Latin, ... or that are terms of classical antiquity ...."

pre. (context archaic technical , or pedantic English) (alternative form of pre- English)