Avoirdupois(redirected from Avoirdupoir)
Also found in: Dictionary, Thesaurus, Medical, Encyclopedia.
A system of measuring weight in which the basic unit is one pound, which is divided into 16 ounces. It is used in the United States, and to a lesser extent in the United Kingdom, Canada, and some former British colonies. Because it is not based on units of 10, it is not used in scientific settings.