from Wiktionary, Creative Commons Attribution/Share-Alike License
- A prefix of Old English origin meaning "against", "back", "in return", "away", represented in Modern English by a-, an-, on-, and in altered form by the reverse-action prefix un- (i.e. unbuckle). Also as the initial letter d in dread (< Old English ondrǣdan).
From Middle English and-, ond-, from Old English and-, ond- ("against, back"), from Proto-Germanic *and-, *anda-, *andi- (“across, opposite, against, away”), from Proto-Indo-European *anta, *anti (“across, forth”), from Proto-Indo-European *ant- (“forehead, foreside, end, limit”). Cognate with Dutch ont-, German ant-, ent-, emp-, Icelandic and-, Gothic (and-), (anda-), Latin ante ("before"), Ancient Greek ἀντί (anti, "against"). (Wiktionary)