ounce

n. [ F. once, fr. L. uncia a twelfth, the twelfth part of a pound or of a foot: cf. Gr. 'o`gkos bulk, mass, atom. Cf. 2d Inch, Oke. ] 1. A unit of mass or weight, the sixteenth part of a pound avoirdupois, and containing 28.35 grams or 4371/2 grains. [ 1913 Webster +PJC ]

2. (Troy Weight) The twelfth part of a troy pound; one troy ounce weighs 31.103486 grams, 8 drams, or 480 grains. [ 1913 Webster +PJC ]

☞ The troy ounce contains twenty pennyweights, each of twenty-four grains, or, in all, 480 grains, and is the twelfth part of the troy pound. The troy ounce is also a weight in apothecaries' weight. [ Troy ounce is sometimes written as one word, troyounce. ] [ 1913 Webster ]

3. Fig.: A small portion; a bit. [ Obs. ] [ 1913 Webster ]

By ounces hung his locks that he had. Chaucer. [ 1913 Webster ]

Fluid ounce. See under Fluid, n. [ 1913 Webster ]