c. 1200, from Old English ær (adv., conj., & prep.) "soon, before (in time)," from Proto-Germanic *airiz, comparative of *air "early" (cognates: Old Saxon, Old Frisian, Old High German er, Dutch eer; German eher "earlier;" Old Norse ar "early;" Gothic air "early," airis "earlier"), from PIE *ayer- "day, morning" (cognates: Avestan ayar "day;" Greek eerios "at daybreak," ariston "breakfast"). The adverb erstwhile retains the Old English superlative ærest "earliest."
