Entry 1 sense Webster, 1913 Vegetarianism /vĕjˌ-ət-ĕr'-ēˌ-ən-ĭzˌ-əm/ · Veg·e·ta·ri·an·ism · IPA /vɛd͡ʒɪˈtɛɹi.ənɪzəm/ 01 n. The theory or practice of living upon vegetables and fruits. 1. The theory or practice of living upon vegetables and fruits.