"accustomed," Middle English contraction of Old English wunod, past participle of wunian "to dwell, inhabit, exist; be accustomed, be used to," from Proto-Germanic *wunen "to be content, to rejoice" (cognates: Old Saxon wunon, Old Frisian wonia "to dwell, remain, be used to," Old High German wonen, German wohnen "to dwell;" related to Old English winnan, gewinnan "to win" (see win, v.) and to wean; from PIE *wen- (1) "strive for, desire." The original meaning of the Germanic verbs was "be content, rejoice."

"habitual usage, custom," c.1400, from wont, adjective and verb.