1911 Encyclopædia Britannica/Ounce
OUNCE, (1) (Through O. Fr. unce, modern once, from Lat. uncia, twelfth part, of weight, of a pound, of measure, of a foot, in which sense it gives the O.Eng. ynce, inch), a unit of weight, being the twelfth part of a pound troy, = 480 grains; in avoirdupois = 437.5 grains, 1⁄16 of a pound. The fluid ounce is a measure of capacity; in the United Kingdom it is equivalent to an avoirdupois ounce of distilled water at 62° F.; in the United States of America it is the 128th part of the gallon, = ¼ gill, = 456.033 grains of distilled water at its maximum density (see Weights and Measures). (2) A name properly applied to the Felis uncia or snow leopard (q.v.). It appears to have been originally used of various species of lynx, and is still sometimes the name of the Canada lynx. The word appears in O. Fr. and Ital. as once and lonce, onza and lonza respectively, and it is usually explained as being due to the confusion of the l with the article, lonce and lonza being changed to l’once or l’onza, and the l’ subsequently dropped. If this be so the word is the same as “lynx,” from the popular Lat. luncia = lyncia, Gr. λύγξ. On the other hand once and onza may be nasalized forms of yūz, the Persian name of the panther.