Tartar

(tar’ -tar) [Low L., tartarum, from Arab., durd, dregs]. I. A hard mineral deposited on the inside of wine-casks, and consisting mainly of acid pota ium tartrate (Cream of T.). T. emetic, antimony and pota ium tartrate. See Antimony. 2. A hard incrustation on the teeth, consisting of mineral and organic matter. 618