ounce

UK: /ˈaʊns/ US: /aʊns/ ,(ouns)

WordReference Random House Learner's Dictionary of American English © 2026

ounce¹ /aʊns/   n. [countable]

1. Weights and Measures a unit of weight equal to 437.5 grains or 1&sfracdenom;16&sfracend; of a pound (28.349 grams) avoirdupois.
2. Weights and Measures a unit of weight equal to 480 grains or 1&sfracdenom;12&sfracend; of a pound (31.103 grams) troy or apothecaries' weight.
3. Weights and Measures a fluid ounce:
   Thirty-two ounces make a quart.
4. a small quantity or portion:
   doesn't have an ounce of sense.

WordReference Random House Unabridged Dictionary of American English © 2026

ounce¹  (ouns), n. 

1. Weights and Measures a unit of weight equal to 437.5 grains or ¹⁄₁₆ pound (28.349 grams) avoirdupois.
2. Weights and Measures a unit of 480 grains, ¹⁄₁₂ pound (31.103 grams) troy or apothecaries' weight.
3. Weights and Measures a fluid ounce.
4. a small quantity or portion.

• Latin uncia twelfth part, inch, ounce, derivative of unus one
• Middle French
• Middle English unce 1350–1400

ounce²  (ouns), n. 

1. Zoology, Mammals See snow leopard. 

• Vulgar Latin *luncea, derivative of Latin lync- (stem of lynx) lynx
• Anglo-French; Old French once, variant of lonce (erroneously taken as l'once the ounce)
• Middle English unce lynx 1300–50

Collins Concise English Dictionary © HarperCollins Publishers::

ounce / aʊns/ noun

1. a unit of weight equal to one sixteenth of a pound (avoirdupois); 1 ounce is equal to 437.5 grains or 28.349 grams
   Abbreviation: oz
2. a unit of weight equal to one twelfth of a Troy or Apothecaries' pound; 1 ounce is equal to 480 grains or 31.103 grams
3. short for fluid ounce
4. a small portion or amount

Etymology: 14th Century: from Old French unce, from Latin uncia a twelfth; from ūnus one

ounce / aʊns/ noun

1. another name for snow leopard

Etymology: 18th Century: from Old French once, by mistaken division of lonce as if l'once, from Latin lynx