Ounce

a measure of weight. The ounce and inch are both akin to the Latin uncia, meaning a twelfth. An ounce is the twelfth part of a pound Troy, or the sixteenth part of a pound avoirdupois. The Troy ounce contains 480 grains; the avoirdupois, 437 1/2. The abbreviation is oz. See Metric System; Avoirdupois