The Collaborative International Dictionary of English v.0.48:

Simulacrum \Sim`u*la"crum\, n.; pl. Simulacra. [L. See
   Simulate.]
   A likeness; a semblance; a mock appearance; a sham; -- now
   usually in a derogatory sense.
   [1913 Webster]

         Beneath it nothing but a great simulacrum. --Thackeray.
   [1913 Webster]