Avoirdupois system

The avoirdupois system is a system for measuring weight. It is based on a pound of 16 ounces or 7,000 grains (453.59 grams). It is the system used in the United States. It is still used by many people in Canada, United Kingdom, and Ireland.

Avoirdupois System Media

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  Finely crafted pan balance or scales with boxed set of standardized gram weights sequenced in units of mass. Such scales are used to make the most accurate of fine measurements, such as in the needs of empirical chemistry.

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  Robust weights like these hexagonal decimal-scaled antiques were used for trade into the late 20th century.

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  The units first became used by wool traders in the Kingdom of England and the Low Countries during the end of the High Middle Ages, as population growth and the Renaissance gave rise to an increasingly numerous town population and a newly established middle class.

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  Comparison of the relative sizes of avoirdupois, Troy, tower, merchant and London pounds.