tartar

American Heritage® Dictionary of the English Language, Fourth Edition

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

Century Dictionary and Cyclopedia

1. n. 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 hard crust, varying from pale pink to dark red according as it has separated from white or red wines. When tartar is purified it forms white crystals having an acid taste and reaction. This is cream of tartar, which is much used in dyeing, in cookery, and also in medicine as a laxative and diuretic. See cream.
2. n. 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.
3. To impregnate with tartar; administer tartar to.
4. n. Same as Tartarus.
5. See Tatar.

Wiktionary

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

GNU Webster's 1913

1. n. (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.
2. n. A correction which often incrusts the teeth, consisting of salivary mucus, animal matter, and phosphate of lime.
3. n. 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.
4. n. A person of a keen, irritable temper.
5. adj. Of or pertaining to Tartary in Asia, or the Tartars.
6. n. See Tartarus.

WordNet 3.0

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