The pound or pound-mass (abbreviations: lb, lbm, lbm, ℔) 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 6999453592370000000♠0.45359237kilograms, and which is divided into 16 avoirdupois ounces.