名詞 jack-knife:

1. a large knife with one or more folding blades
   同義詞：clasp knife, jackknife
2. a dive in which the diver bends to touch the ankles before straightening out
   同義詞：jackknife

動詞 jack-knife:

1. dive into the water bending the body at the waist at a right angle, like a jackknife
   同義詞：jackknife

1. A heavy lorry has jack-knifed on the motorway, causing long delays.
   一輛重型鉸接貨車在高速公路上撞成V字形，耽擱了很長時間。