benzodiazepinePronunciation: /ˌbɛnzəʊdʌɪˈeɪzɪpiːn, -ˈazəpiːn/Definition of benzodiazepine noun Medicine any of a class of heterocyclic organic compounds used as tranquillizers, such as Librium and Valium. Origin: 1930s: from benzene + di-1 + azo- + epi- + -ine4benzodiazepine in other Oxford dictionaries Definition of benzodiazepine in the US English dictionary