any weight unit used in pharmacy; an ounce is equal to 480 grains and a pound is equal to 12 ounces

Of, or relating to, troy weight, Of or expressed in troy weight, noun_ the weight which gold and silver, jewels, and the like, are weighed. It was so named from Troyes, in France, where it was first adopted in Europe. The troy ounce is supposed to have been brought from Cairo during the crusades. In this weight the pound is divided into 12 ounces, the ounce into 20 pennyweights, and the pennyweight into 24 grains; hence, the troy ounce contains 480 grains, and the troy pound contains 5760 grains. The avoirdupois pound contains 7000 troy grains; so that 175 pounds troy equal 144 pounds avoirdupois, or 1 pound troy = 0.82286 of a pound avoirdupois, and 1 ounce troy = 117/175 or 1.09714 ounce avoirdupois. Troy weight when divided, the pound into 12 ounces, the ounce into 8 drams, the dram into 3 scruples, and the scruple into 20 grains, is called apothecaries' weight, used in weighing medicines, etc. In the standard weights of the United States, the troy ounce is divided decimally down to the 1/10000 part, a system of weights used for precious metals and gemstones; based on a 12-ounce pound and an ounce of 480 grains, an ancient city in Asia Minor that was the site of the Trojan War