1 [ouns]
a unit of weight equal to 437.5 grains or 1/16 pound (28.35 grams) avoirdupois.
a unit of 480 grains, 1/12 pound (31.1 grams) troy or apothecaries' weight.
a small quantity or portion.

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

Dictionary.com Unabridged


2 [ouns]

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

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Cite This Source Link To ounce
World English Dictionary
ounce1 (aʊns)
1.  oz a unit of weight equal to one sixteenth of a pound (avoirdupois); 1 ounce is equal to 437.5 grains or 28.349 grams
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
[C14: from Old French unce, from Latin uncia a twelfth; from ūnus one]

ounce2 (aʊns)
another name for snow leopard
[C18: from Old French once, by mistaken division of lonce as if l'once, from Latin lynx]

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
Cite This Source
Word Origin & History

"unit of weight," early 14c., from O.Fr. unce (12c.), from L. uncia "one-twelfth part" (of a pound, foot, etc.), from L. unus "one" (see one). The L. word had been adopted in O.E. as ynce (see inch). It was one-twelfth of a pound in the Troy system
of weights, but one-sixteenth in avoirdupois. Abbreviation oz. is from It. onza. Also used in M.E. as a measure of time (7.5 seconds) and length (about 3 inches).

"wildcat," c.1300, from O.Fr. once, from lonce, with l- mistaken as definite article, from V.L. *luncea, from L. lyncea "lynx-like," from lynx (see lynx). Originally the common lynx, later extended to other wildcats, now mainly used of the mountain-panther or snow leopard of Asia.
Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
American Heritage
Medical Dictionary

ounce (ouns)
Abbr. oz, oz.

  1. A unit of weight in the U.S. Customary System, an avoirdupois unit equal to 437.5 grains or 28.35 grams.

  2. A unit of apothecary weight equal to 480 grains or 31.10 grams.

  3. A fluid ounce.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source
American Heritage
Science Dictionary
ounce   (ouns)  Pronunciation Key 
  1. A unit of weight in the US Customary System equal to 1/16 of a pound or 437.5 grains (28.35 kilograms). See Table at measurement.

  2. See fluid ounce.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
American Heritage
Idioms & Phrases


In addition to the idiom beginning with ounce, also see more bang for the buck (bounce for the ounce).

The American Heritage® Dictionary of Idioms by Christine Ammer.
Copyright © 1997. Published by Houghton Mifflin.
Cite This Source
Example sentences
If put to the pinch, an ounce of loyalty is worth a pound of cleverness.
To that, a group of researchers is saying that an ounce of prevention is worth a pound of cure.
So the industry has adopted a strategy that counters a pound of sugar with an ounce of nutrition.
Sponges have to filter about a ton of water for each ounce of food they ingest.
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature