Entry 1 sense Webster, 1913 Orvietan /ôr'vē-ātʹn/ · Or·vi·e·tan · IPA /ˌɔːvɪˈeɪtən/ 01 n. A kind of antidote for poisons; a counter poison formerly in vogue. 1. A kind of antidote for poisons; a counter poison formerly in vogue.[Obs.]