a non-metric system of weights used in the UK, the US, and other countries, whose basic units are the ounce, the pound, the hundredweight and the ton nouna non-metric system of weights used in the UK, the US, and other countries, whose basic units are the ounce, the pound, the hundredweight and the ton(NoteThe system is now no longer officially used in the UK)COMMENTAvoirdupois weight is divided into drams (16 drams = 1 ounce); ounces (14 ounces = one pound); pounds (100 pounds = 1 hundredweight); hundredweight (20 hundredweight = 1 ton). Avoirdupois weights are slightly heavier than troy weights with the same names: the avoirdupois pound equals 0.45kg, whereas the troy pound equals 0.37kg. See also TROY.