Cār'at, n.

n. [Fr. carat, It. carato, O. Pg. quirate, N. Pg. & Sp. quilate, Ar. qirrāt, qîrât, a bean or pea shell, a weight of four grains, carat, which word the Arabians borrowed from Gr. κεράτιον, a little horn, the fruit of the carob-tree, a weight, carat.]

1. The weight of four grains, used by jewelers in weighing precious stones and pearls.
2. A twenty-fourth part:—a denomination used in determining the proportionate fineness of gold. The whole mass of gold to be estimated is divided into twenty-four equal parts, and said to be of so many carats, according to the number of twenty-fourths of pure metal; as, gold of eighteen or twenty-two carats.