/'tɑ:tə(r); `tɑrtɚ/
n [U]
1 hard chalky deposit that forms on the teeth 牙垢; 牙石. Cf 参看 plaque2.2 reddish deposit that forms on the inside of a cask in which wine is fermented 酒石（形成于酒的发酵桶内侧者）.

/'tɑ:tə(r); `tɑrtɚ/
n person who has a violent temper or is difficult to deal with 脾气暴躁的人; 难对付的人.

n
[Date: 1300-1400; Language: Medieval Latin;Origin: tartarum]
[U]
a hard substance that forms on your teeth
[C]informal BrE someone who has a violent temper
　She's a real tartar.