jackknife [ 'dʒæknaifiŋ ]

• n.
  • a large knife with one or more folding blades

    同义词： clasp knife

  • 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

以上来源于: WordNet