[′brid·ish grav·ə′tā·shən·əl ′sis·təm əv ′yü·nəts] (physics) A measurement system based on the foot, the second, and the slug mass; 1 slug weighs 32.174 pounds at sea level and 45° latitude, and equals 14.594 kilograms. Also known as British engineering system of units; engineer's system of units.