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, ordren, "give order to, to arrange in a row or rank," from order (n.). Sense of "set or keep in order" is from c. 1500. Meaning "to give commands for or to, instruct authoritatively" is from 1540s; that of "command to be made, done, or issued" is from 1763. Related: Ordered; ordering.