noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   A unit of mass equal to the weight, on earth (subject to standard gravity), of a mass of one avoirdupois pound, equal to about 453.592 grams. Symbol lbm or lbₘ.

   "On the moon, however the weight of a pound-mass (lb or lbm) is only about one sixth of a pound-force (lbf)."

Example

More examples

"On the moon, however the weight of a pound-mass (lb or lbm) is only about one sixth of a pound-force (lbf)."

Etymology

From pound + mass, to differentiate from the unit of weight.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.