​

word-forming element meaning "back to the original place; again, anew, once more," also with a sense of "undoing," c. 1200, from Old French and directly from Latin re- "again, back, anew, against," "Latin combining form conceivably from Indo-European *wret-, metathetical variant of *wert- "to turn" [Watkins]. The Latin prefix became red- before

vowels and h-, as in redact, redeem, redolent, redundant.