Source : Webster's Revised Unabridged Dictionary (1913)

Impalement \Im*pale"ment\, n.
   1. The act of impaling, or the state of being impaled.
      --Byron.

   2. An inclosing by stakes or pales, or the space so inclosed.
      --H. Brooke.

   3. That which hedges in; inclosure. [R.] --Milton.

   4. (Her.) The division of a shield palewise, or by a vertical
      line, esp. for the purpose of putting side by side the
      arms of husband and wife. See {Impale}, 3.

Source : WordNet®

impalement
     n : the act of piercing with a sharpened stake as a form of
         punishment or torture