Avoirdupois (French, to have weight), a system of weights based on a pound of sixteen ounces or 7,000 Troy grains. It was introduced into England from Bayonne, France, about 1300 A. D. It has been inherited by the colonies of England. It is used chiefly for the weighing of coarse commodities. The principal denominations are the ounce, pound, hundredweight, and ton,--the latter consisting of twenty hundredweight. See TON.