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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 ...."