The Collaborative International Dictionary of English v.0.48:

Gilding \Gild"ing\ (g[i^]ld"[i^]ng), n.
   1. The art or practice of overlaying or covering with gold
      leaf; also, a thin coating or wash of gold, or of that
      which resembles gold.
      [1913 Webster]

   2. Gold in leaf, powder, or liquid, for application to any
      surface.
      [1913 Webster]

   3. Any superficial coating or appearance, as opposed to what
      is solid and genuine.
      [1913 Webster]

   Gilding metal, a tough kind of sheet brass from which
      cartridge shells are made.
      [1913 Webster]

WordNet (r) 3.0 (2006):

gilding metal
    n 1: a brass that is rich in copper; used to make articles that
         were to be gilded