| a parachute jump from the tops of tall manmade or natural objects, usually from 1,000 feet (305 m) or less. |
BASE jump  (bās) n. A parachute jump from high structures and precipitous earth formations, typically from heights of 305 meters (1,000 feet) or less. [b(uilding) + a(ntenna tower) + s(pan)1 + e(arth) + jump.] BASE'-jump' v., BASE jumper n. |