Pro- (Gr.), before, as prologue, programme, prophet. [Gr. pro; cog. with L. pro-, Sans. pra, Eng. for (prep.).]
Pro- (L.), forth, forward, before, instead, as project; instead of, from the idea of being before, as pronoun, proconsul. Appearing also as por-, pour-, pr-, prof-, pur-, and as prod- in prodigal.—Of Fr. origin, proceed, purchase, purpose, pursue, purvey. [Cog. with pro- (Gr.), which see.]
Pros- (Gr.), towards, as proselyte, prosody.
Proto-, Prot- (Gr.), first, as prototype, protoxide. [Gr. prōtos, first.]
Pur-. See under Pour-.
Re-, Red-, Ren- (L.), change of place or condition, as in remove, reunion (an assemblage of things or persons formerly apart); hence, change of motion from one direction to the opposite='back,' 'again,'as retract, resound, redeem, redolent. It appears as ren- in render, &c.; as r- in rally, rampart; as ra- in ragout. In rebuild, remind, &c. it has been prefixed to English words.
Retro- (L.), back, backwards, as retrospect, retrograde.—Of Fr. origin, rereward, arrear, &c.
S- for Se-, as in sure; for Dis-, as in spend; for Ex-, as in sample; for Sub-, as in sombre.
Se-, Sed- (L.), without, as secure; aside, as seduce, secede, sedition; appearing as s- in sure, sober.
Semi- (L.), half, as semicircle. [L.; cog. with Gr. hēmi.]