Source : Webster's Revised Unabridged Dictionary (1913)

Pruning \Prun"ing\, n.
   1. The act of trimming, or removing what is superfluous.

   2. (Falconry) That which is cast off by bird in pruning her
      feathers; leavings. --Beau. & Fl.

   {Pruning hook}, or {Pruning knife}, cutting instrument used
      in pruning trees, etc.

   {Pruning shears}, shears for pruning trees, vines, etc.

Source : WordNet®

pruning knife
     n : a knife with a curved or hooked blade