vegetarianism UK /vɛd͡ʒɪˈtɛəɹi.ənɪzəm/US /vɛd͡ʒɪˈtɛɹi.ənɪzəm/ noun1 •The practice of following a vegetarian diet.Vegetarianism, he said, is an idea “that has three things going for it all at once—economics, health and compassion.” — 1975 formsVegetarianisms · vegetarianisms