tartar, dental, precipitate of saliva that accumulates around teeth at the gum line. Composed primarily of calcium salts, tartar forms as a hard brownish substance that irritates gums and causes them to recede. Inflammation of this tissue may lead to the recession and infection of the bones in which teeth are imbedded and result in the loosening and loss of teeth. As symptoms may not become apparent until serious damage has occurred, periodic dental visits for the removal of tartar are recommended.

tartar emetic, poisonous, odorless, transparent rhombic crystals or white powder with a metallic, sweetish taste. Chemically, it is potassium antimony tartrate, KSbC₄H₄O₇·1/2H₂O. It is used as a mordant in dyeing. Medically, it was formerly used as an emetic and expectorant, to produce sweating, and in the treatment of several diseases, but had frequent toxic side effects.

tartar or argol, impure potassium hydrogen tartrate deposited as a crust in fermenting vessels during wine making. When purified, it yields cream of tartar. Tartar is the chief natural source of tartaric acid.

cream of tartar, white crystalline powder. Chemically it is potassium hydrogen tartrate, KC₄H₅O₆, the acidic potassium salt of tartaric acid. It is used as the leavening agent in baking powders. An impure form, called tartar or argol, forms naturally during the fermentation of grape juice into wine and crystallizes in the wine casks.