- Avoirdupois
The avoirdupois (IPAEng|ˌævərdəˈpɔɪz; French IPA2|avwaʀdypwɑ) system is a system of weights (or, properly,
mass ) based on a pound of sixteenounce s. It is the everyday system of weight used in theUnited States . It is still widely used by many people inCanada and theUnited Kingdom despite the official adoption of themetric system , including the compulsory introduction of metric units in shops. It is consideredFact|date=May 2007 more modern than the alternative troy or apothecary or the medieval English mercantile and Tower systems.History of the term
The word "avoirdupois" is from French and
Middle English (Anglo-French) "avoir de pois", "goods of weight" or "goods sold by weight", fromOld French "aveir de peis", literally "goods of weight" (Old French "aveir", "property, goods", also "to have", comes from theLatin "habere", "to have, to hold, to possess property"; "de" = "from", cf. Latin; "peis" = "weight", from Latin "pensum"). This term originally referred to a class of merchandise: "aveir de peis", "goods of weight", things that were sold in bulk and were weighed on large steelyards or balances. Only later did it become identified with a particular system of units used to weigh such merchandise. The imaginative orthography of the day and the passage of the term through a series of languages (Latin, Anglo-French and English) has left many variants of the term, such as "haberty-poie" and "haber de peyse". (The Norman "peis" became the Parisian "pois". In the 17th century "de" was replaced with "du".)Original forms
These are the units in their original French forms:
Internationalization
In the avoirdupois system, all units are multiples or fractions of the pound, which is now defined as 0.45359237 kg in most of the English-speaking world since 1959. (See the
Mendenhall Order for references.)Due to the ambiguous meanings of "weight" as referring to both mass and force, it is sometimes erroneously asserted that the pound is only a unit of force. However, as defined above the pound is a unit of mass, which agrees with common usage. Also see
pound-force andpound-mass .ee also
*
French units of measurement
*Apothecaries' system
*Imperial unit
*Troy weight
*United States customary units References
Wikimedia Foundation. 2010.