# 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 **lb _{m}**[3] (for most pound definitions),

**#**(chiefly in the U.S.),[4] and

**℔**[5] or

**″̶**[6] (specifically for the apothecaries' pound).

pound | |
---|---|

General information | |

Unit system | |

Unit of | mass |

Symbol | lb |

Conversions | |

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*.