Merriam-Webster Collegiate Dictionary - tartar

 adjective see tartar II TARTAR  I. noun  Etymology: Middle English, from Anglo-French, from Medieval Latin ~um  Date: 14th century  1. a substance consisting essentially of cream of ~ 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 ~ 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 Tatar — 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