Mŭs'tard, n.

noun

n. [O. Fr. moustarde, Fr. moutarde, Pr., It., & Pg. mostarda, Sp. mostaza, from Lat. mustum, must, because it is mixed with it.] (Bot.) A plant of the genus Sinapis, and its seed, which has a pungent taste. It is used externally in cataplasms, and internally as a diuretic and irritant. A condiment is prepared from the pulverized seeds of the plant.

A botanical illustration of a mustard plant with flowering stems, leaves, and seed pods. — Mustard.