ounce

Etymology 1

From Middle English ounce, unce, from Middle French once, from Latin uncia (“Roman ounce, various similar units”), ultimately from Proto-Indo-European *óynos (“one”). Doublet of a, one, inch, uncia, onça, onza, oka, ouguiya, and awqiyyah.

noun

1. An avoirdupois ounce, weighing ¹⁄₁₆ of an avoirdupois pound, or 28.3495 grams.
2. A troy ounce, weighing ¹⁄₁₂ of a troy pound, or 480 grains, or 31.1035 grams.
3. A US fluid ounce, with a volume of ¹⁄₁₆ of a US pint, 1.8047 cubic inches or 29.5735 millilitres.
4. A British imperial fluid ounce, with a volume of ¹⁄₂₀ of an imperial pint, 1.7339 cubic inches or 28.4131 millilitres.
5. (figurative) Any small amount, a little bit.
   He didn't feel even an ounce of regret for his actions.

Etymology 2

From Middle French once, from Old French lonce (“lynx”), by false division (the l was thought to be the article), from Italian lonza, ultimately from Ancient Greek λύγξ (lúnx, “lynx”). Doublet of onza.

noun

1. (now archaic) A large wild feline, such as a lynx or cougar.
2. Synonym of snow leopard, Panthera uncia.
3. (cryptozoology) Synonym of onza, a particularly aggressive cougar or jaguarundi in Mexican folklore.
   The ounce, a leopard-like creature, is dreaded for its depredations by the Indians of Brazil. 1911, James George Frazer, The Golden Bough, volume 8, page 235