tartar

I. noun Etymology: Middle English, from Anglo-French, from Medieval Latin tartarum Date: 14th century 1. a substance consisting essentially of cream of tartar that is derived from the juice of grapes and deposited in wine casks together with yeast and other suspended matters as a pale or dark reddish crust or sediment; especially a recrystallized product yielding cream of tartar on further purification 2. an incrustation on the teeth consisting of plaque that has become hardened by the deposition of mineral salts (as calcium carbonate) II. noun Etymology: Middle English Tartre, from Middle French Tartare, probably from Medieval Latin Tartarus, modification of Persian Tātār — more at Tatar Date: 14th century 1. capitalized a native or inhabitant of Tartary 2. capitalized Tatar 2 3. often capitalized a person of irritable or violent temper 4. one that proves to be unexpectedly formidable • Tartar adjective • Tartarian adjective