Ounce

Ounce (Lat. uncia), the twelfth part of the as or libra (pound), or indeed the twelfth part of any magnitude, whether of length, surface, or capacity. Hence inch, the twelfth part of a foot. In Troy weight the ounce is divided into 480 grains, and 12 ounces make a pound; the ounce in Avoirdupois weight contains 437½ grains Troy, and 16 of them go to the pound.