Pound (mass)

The pound or pound-mass is a unit of mass used in British imperial and United States customary systems of measurement. Various definitions have been used; the most common today is the international avoirdupois pound, which is legally defined as exactly 0.45359237 kilograms, and which is divided into 16 avoirdupois ounces.[1] The international standard symbol for the avoirdupois pound is lb;[2] an alternative symbol is lbm[3] (for most pound definitions), # (chiefly in the U.S.),[4] and [5] or ″̶[6] (specifically for the apothecaries' pound).

One-pound avoirdupois weight, from the Musée des Arts et Métiers
General information
Unit system
Unit ofmass
1 lb in ...... is equal to ...
   SI units   0.45359237 kg
   Avoirdupois   16 ounces

The unit is descended from the Roman libra (hence the abbreviation "lb"). The English word pound is cognate with, among others, German Pfund, Dutch pond, and Swedish pund. These units are historic and are no longer used (replaced by the metric system).

Usage of the unqualified term pound reflects the historical conflation of mass and weight. This accounts for the modern distinguishing terms pound-mass and pound-force.

Share this article:

This article uses material from the Wikipedia article Pound (mass), and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.