A unit which used to measure the mass of any substance; except precious gems and metals, and drugs: Avoirdupois was used in the UK from 1856 and 1963, and in the USA between 1886 and 1959.

Avoirdupois included the pound, short and long tons, ounce, and dram.

Avoirdupois was a system of units of mass based on the pound (0.45 kilograms), which consists of 16 ounces (each of 16 drams) or 7,000 grains (each equal to 65 milligrams).