: any of various units of mass and weight: as a: a unit of troy weight equal to 12 troy ounces or 5760 grains or 0.3732417216 kilogram formerly used in weighing gold, silver, and a few other costly materials—called also troy poundb: a unit of avoirdupois weight equal to 16 avoirdupois ounces or 7000 grains or 0.45359237 kilogram—called also avoirdupois pound
Unit of weight in the avoirdupois system, the traditional European system of weight (incorporated into the British Imperial system and the U.S. system of weights and measures), equal to 16 oz, 7,000 grains, or 0.4536 kg. It is also a unit of weight in the troy and apothecaries' systems (two other traditional systems of weight), equal to 12 troy or apothecaries' oz, 5,760 grains, or 0.37 kg. Its Roman ancestor, the libra, is the source of the abbreviation lb. The troy pound is used for precious metals, the apothecaries' pound for drugs. The British monetary pound is linked historically with the minting of silver coins (sterlings). Large payments were reckoned in pounds of sterlings, later shortened to pounds sterling. See alsogram; International System of Units; measurement; metric system; ounce.