carat

n. [ F. carat (cf. It. carato, OPg. quirate, Pg. & Sp. quilate), Ar. qīrāt bean or pea shell, a weight of four grains, a carat, fr. Gr. kera`tion a little horn, the fruit of the carob tree, a weight, a carat. See Horn. ] 1. The weight by which precious stones and pearls are weighed. [ 1913 Webster ]

☞ The carat equals three and one fifth grains Troy, and is divided into four grains, sometimes called carat grains. Diamonds and other precious stones are estimated by carats and fractions of carats, and pearls, usually, by carat grains. Tiffany. [ 1913 Webster ]

2. A twenty-fourth part; -- a term used in estimating the proportionate fineness of gold. [ 1913 Webster ]

☞ A mass of metal is said to be so many carats fine, according to the number of twenty-fourths of pure gold which it contains; as, 22 carats fine (goldsmith's standard) = 22 parts of gold, 1 of copper, and 1 of silver. [ 1913 Webster ]