The Collaborative International Dictionary of English v.0.48:

Denudation \Den`u*da"tion\ (?; 277), n. [L. denudatio: cf. F.
   d['e]nudation.]
   1. The act of stripping off covering, or removing the
      surface; a making bare.
      [1913 Webster]

   2. (Geol.) The laying bare of rocks by the washing away of
      the overlying earth, etc.; or the excavation and removal
      of them by the action of running water.
      [1913 Webster]

WordNet (r) 3.0 (2006):

denudation
    n 1: the removal of covering [syn: denudation, stripping,
         uncovering, baring, husking]