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Avoirdupois [ ˌævədəˈpɔɪz, ˌævwɑːdjuːˈpwɑː ] is an Anglo-American system of measurement for mass based on one pound , consisting of 16 ounces . It is a traditional commercial weight and is not used for precious metals and medicines. The troy ounce or troy ounce is used here. Although it was officially superseded by the metric system , it is still common in everyday life in the United States , Canada , the United Kingdom and its former colonies.


The word avoirdupois is derived from the old French aveir de peis and, in the 15th century, the Middle English avoir de pois and means goods of weight ( aveir: goods, possessions; avoir: have; peis or pois: weight).

Definition and conversion

The following table shows the conversions of the units of the Avoirdupois system. The pound as the basic unit has been defined as exactly 453.59237 g of the metric system since July 1, 1959. Before 1959, the United Kingdom used the mass of a corresponding weight as the basis; this was determined to be 453.592338 g. In the USA from 1893 to 1959 there was already a definition in the metric system with the Mendenhall Order , according to which the mass of the Avoirdupois pound was exactly 453.5924277 g.

unit German Abbr. size kg
Commercial weights , Avoirdupois
grain grain gr. 17000 pounds 0.000.00006479891
dram drachma dr. 116 ounce 0.000.001771845195312500
ounce , coll. lid ounce oz. 116 pounds 0.000.028349523125
pound lb lb., pd., #, lb m . 7000 grain 0.000.453592370
short Avoirdupois
quarter Quarter penny   ¼ hundredweight 0.011.339809250
hundredweight , cental Hundredweight cwt. 100 pounds 0.045.359237
volume ton T., to. 20 hundredweight 0.907.18474
long Avoirdupois
stone stone st. 14 pounds 0.006.350293180
quarter Quarter penny qu., qr. l. 2 stone 0.012.700586360
hundredweight Hundredweight cwt. 4 quarters 0.050.80234544
volume ton T., to. 20 hundredweight 1,016.0469088

See also


Individual evidence

  1. ^ Avoirdupois on Online Dictionary.com - Etymology Dictionary Douglas Harper, Historian. Accessed: July 26, 2010 (English).
  2. pound avoirdupois on sizes.com. Retrieved August 30, 2014 .