What does ounce mean?
An ounce is primarily a unit of weight equal to one-sixteenth of a pound, or approximately 28.35 grams. It is used for measuring many everyday goods, including food, ingredients, precious metals, and parcels, while “troy ounce” is used in the bullion and precious-metals trade. The word also refers to specific units of liquid volume when qualified as “fluid ounce.” By extension, “an ounce of” can mean a very small quantity, often with an implication that something is barely present: “not an ounce of doubt.” In figurative expressions, an ounce can represent a small amount of an abstract quality, such as patience, courage, or evidence. This breadth of meaning allows the word to function both as a precise measurement and as a vivid way of describing something scarce or insignificant.
nounA unit of weight equal to one-sixteenth of a pound, or approximately 28.35 grams. By extension, the word can mean a very small amount of something, and it also names units of liquid volume, such as the US fluid ounce.
- A unit of weight equal to one-sixteenth of an avoirdupois pound, or approximately 28.35 grams.
- A very small amount of something.
- A unit of liquid volume, especially the US fluid ounce or the British imperial fluid ounce.
"She added an ounce of yeast to the warm water."
"The package contains three ounces of dried herbs."
"There was not an ounce of evidence that the story was true."
The standard plural is “ounces,” used for both units of weight and units of liquid volume.
"The recipe calls for two ounces of flour and one fluid ounce of milk."
An ounce is tiny by everyday standards, but precious metals are measured in ounces—and gold's history has been shaped by its weight.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of ounce
The word comes through Old French once, meaning “ounce,” from Latin uncia, a twelfth part and the name of a unit of weight. Latin uncia is also the source of “inch,” while “uncial” was derived from the same Latin term. The precise origin of uncia is uncertain, although it is traditionally connected with a form meaning “one-twelfth.”
How ounce is actually used
In ordinary British and American usage, an ounce usually means a unit of weight. “Fluid ounce” is required when referring to a volume of liquid, and the exact volume differs between US and British systems. The figurative sense “an ounce of” is established and often appears in expressions such as “an ounce of courage.”