Pound (mass)

The pound or pound-mass is a unit of mass used in the imperial, United States customary and other systems of measurement. A number of different definitions have been used, the most common today being the international avoirdupois pound which is legally defined as exactly 0.45359237 kilograms. The unit is descended from the Roman libra (hence the abbreviation “lb”); the name pound is a Germanic adaptation of the Latin phrase libra pondo, ‘a pound by weight’.