avoirdupois weight
Noun
Meaning
a system of weights based on the 16-ounce pound (or 7,000 grains)
Source: WordNetSynonyms
Hypernyms
Examples
Of these, the avoirdupois weight is the most common system used in the U.S., although Troy weight is still used to weigh precious metals.
Troy weight, avoirdupois weight, and apothecaries' weight are all built from the same basic unit, the grain, which is the same in all three systems.