大折合式刀,镰刀式跳水弯身用大折刀切
Jackknife \Jack"knife`\, n. A large, strong clasp knife for the pocket; a pocket knife.
jackknife
n 1: a large knife with one or more folding blades [syn: {clasp
knife}]
2: a dive in which the diver bends to touch the ankles before
straightening out
v : dive into the water bending the body at the waist at a right
angle, like a jackknife
[also: {jackknives} (pl)]