Etymology 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.
1
An avoirdupois ounce, weighing ¹⁄₁₆ of an avoirdupois pound, or 28.349523125 grams.
2
A troy ounce, weighing ¹⁄₁₂ of a troy pound, or 480 grains, or 31.1034768 grams.
3
A US fluid ounce, with a volume of ¹⁄₁₆ of a US pint, 1.804688 cubic inches or 29.5735295625 millilitres.
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A British imperial fluid ounce, with a volume of ¹⁄₂₀ of an imperial pint, 1.733871 cubic inches or 28.4130625 millilitres.
5
Figuratively, In the negative Any small amount, a little bit.
He didn't feel even an ounce of regret for his actions.
Etymology 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 and lynx.
1
Archaic A large wild feline, such as a lynx or cougar.
The Ounce or the vvilde Cat, is as big as a mungrell dog, this creature is by nature feirce, and more dangerous to bee met vvithall than any other creature, not fearing eyther dogge or man; […]1634, William Wood, “Of the Beasts that Live on the Land”, in New Englands Prospect. A True, Lively, and Experimentall Description of that Part of America, Commonly Called New England; […], London: […] Tho[mas] Cotes, for Iohn Bellamie, […], →OCLC, 1st part, page 23:
Halloa! another prey, The nimble Antelope! The ounce is freed; one spring, And his talons are sheath’d in her shoulders, And his teeth are red in her gore.1801, Robert Southey, “(please specify the page)”, in Thalaba the Destroyer, volume (please specify |volume=I or II), London: […] [F]or T[homas] N[orton] Longman and O[wen] Rees, […], by Biggs and Cottle, […], →OCLC:
2
Synonym of snow leopard, Panthera uncia.
3
Biology, Cryptozoology, Natural sciences, Zoology 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: