Definition:Avoirdupois/Ounce

Definition
The ounce is an imperial unit of mass.
 * $1$ ounce $= \dfrac 1 {16}$ pound $= 437 \cdotp 5$ grains $= 28 \cdotp 34952 \, 3125$ grams.

This is the international avoirdupois ounce which is in common use.

The gram equivalent is defined to be exact.

Also see

 * Definition:Ounce
 * Definition:Apothecaries' Ounce
 * Definition:Troy Ounce