in botany, a genus of the syngenesia polygamia æqualis clas. The receptacle is naked; and the calyx is hemispherical and imbricated. There are eight species, only one of them, viz. the vulgare, or common tanzy, a native of Britain.

Tanzy, considered as a medicine, is a moderately warm bitter, and is much extolled by some in hysterical complaints, especially if proceeding from a deficiency or suppression of the uterine purgations: its seeds and leaves have been in considerable esteem as anthelmintics; and are said to be good in colics and flatulencies.

TANGENT of an arch is a right-line drawn perpendicularly from the end of a diameter, falling to one extremity of the arch, and terminated by a right-line drawn from the centre through the other end of the arch, and called the secant. See GEOMETRY.