The Collaborative International Dictionary of English v.0.48:

Clasp \Clasp\, n.
   1. An adjustable catch, bent plate, or hook, for holding
      together two objects or the parts of anything, as the ends
      of a belt, the covers of a book, etc.
      [1913 Webster]

   2. A close embrace; a throwing of the arms around; a
      grasping, as with the hand.
      [1913 Webster]

   Clasp knife, a large knife, the blade of which folds or
      shuts into the handle.

   Clasp lock, a lock which closes or secures itself by means
      of a spring.
      [1913 Webster]

WordNet (r) 3.0 (2006):

clasp knife
    n 1: a large knife with one or more folding blades [syn: clasp
         knife, jackknife]