TROY WEIGHT

traditional European system of weight based on the grain, pennyweight (24 grains), ounce (20 pennyweights), and pound (12 ounces). The troy grain, pennyweight, and ounce have been used since the Middle Ages to weigh gold, silver, and other precious metals. The name derives from the city of Troyes, site of one of the major medieval fairs. The troy pound was adopted by the U.S. Mint for the regulation of coinage in 1828. The troy pound is equal to the apothecaries' pound and to approximately 0.82 avoirdupois pound and 0.37 kilogram.