noun

• An avoirdupois ounce, weighing ¹⁄₁₆ of an avoirdupois pound, or 28.3495 grams.
• A troy ounce, weighing ¹⁄₁₂ of a troy pound, or 480 grains, or 31.1035 grams.
• A US fluid ounce, with a volume of ¹⁄₁₆ of a US pint, 1.8047 cubic inches or 29.5735 millilitres.
• A British imperial fluid ounce, with a volume of ¹⁄₂₀ of an imperial pint, 1.7339 cubic inches or 28.4131 millilitres.
• (figurative) Any small amount, a little bit.
• (now archaic) A large wild feline, such as a lynx or cougar.
• Synonym of snow leopard, Panthera uncia.
• (cryptozoology) Synonym of onza, a particularly aggressive cougar or jaguarundi in Mexican folklore.