The English units of mass are
-- the pound-mass . . . the mass that weighs a pound on Earth
-- the Slug . . . the mass that weighs 32.2 pounds on Earth
The common English units of mass are the pound-mass and the slug. The pound-mass is often used in everyday contexts, while the slug is primarily used in physics and engineering. It's important to distinguish between mass (amount of matter) and weight (force due to gravity).
;