ounce
An avoirdupois ounce, weighing 16 of an avoirdupois pound, or 28.349523125 grams.
Other meanings
A troy ounce, weighing 12 of a troy pound, or 480 grains, or 31.1034768 grams.
A US fluid ounce, with a volume of 16 of a US pint, 1.804688 cubic inches or 29.5735295625 millilitres.
Word history
From Latin "uncia" (Roman ounce, various similar units).
Where this comes from
This definition is adapted from “ounce” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.