tartar

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Dentistry A hard yellowish deposit on the teeth, consisting of organic secretions and food particles deposited in various salts, such as calcium carbonate.
• noun A reddish acid compound, chiefly potassium bitartrate, found in the juice of grapes and deposited on the sides of casks during winemaking.

from The Century Dictionary.

• noun Impure acid potassium tartrate, also called argal or argol, deposited from wines completely fermented, and adhering to the sides of the casks in the form of a hard crust, varying from pale pink to dark red according as it has separated from white or red wines.
• noun An earthy substance which occasionally concretes upon the teeth, and is deposited from the saliva. It consists of salivary mucus, animal matter, and calcium phosphate.
• To impregnate with tartar; administer tartar to.
• See Tatar.
• noun Same as Tartarus.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Of or pertaining to Tartary in Asia, or the Tartars.
• noun See Tartarus.
• noun A native or inhabitant of Tartary in Asia; a member of any one of numerous tribes, chiefly Moslem, of Turkish origin, inhabiting the Russian Europe; -- written also, more correctly but less usually, Tatar.
• noun A person of a keen, irritable temper.
• noun [Colloq.] to lay hold of, or encounter, a person who proves too strong for the assailant.
• noun (Chem.) A reddish crust or sediment in wine casks, consisting essentially of crude cream of tartar, and used in marking pure cream of tartar, tartaric acid, potassium carbonate, black flux, etc., and, in dyeing, as a mordant for woolen goods; -- called also argol, wine stone, etc.
• noun A correction which often incrusts the teeth, consisting of salivary mucus, animal matter, and phosphate of lime.
• noun (Chem.) See under Cream.
• noun (Med. Chem.) a double tartrate of potassium and basic antimony. It is a poisonous white crystalline substance having a sweetish metallic taste, and used in medicine as a sudorific and emetic.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A red compound deposited during wine making; mostly potassium hydrogen tartrate - a source of cream of tartar.
• noun A hard yellow deposit on the teeth.
• noun sometimes capitalised A fearsome or angrily violent person.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an incrustation that forms on the teeth and gums
• noun a salt used especially in baking powder
• noun a fiercely vigilant and unpleasant woman
• noun a member of the Mongolian people of central Asia who invaded Russia in the 13th century