Ounce (oz)
Definition: An ounce (symbol: oz) is a unit of mass equal to 1/16 of a pound, or approximately 28.3495 grams. The international avoirdupois ounce has been the standard since 1959.
History/origin: The ounce has Roman roots. The Roman uncia was 1/12 of a Roman pound. Over time the number of ounces per pound settled at 16 in the avoirdupois system used for most everyday goods.
Current use: Ounces are commonly used in the United States for food portions, postal weights, and product packaging. The troy ounce is a separate unit used specifically for precious metals like gold and silver.
