The Collaborative International Dictionary of English v.0.48:

Mock \Mock\, a.
   Imitating reality, but not real; false; counterfeit; assumed;
   sham.
   [1913 Webster]

         That superior greatness and mock majesty. --Spectator.
   [1913 Webster]

   Mock bishop's weed (Bot.), a genus of slender umbelliferous
      herbs (Discopleura) growing in wet places.

   Mock heroic, burlesquing the heroic; as, a mock heroic
      poem.

   Mock lead. See Blende (
   a ).

   Mock nightingale (Zool.), the European blackcap.

   Mock orange (Bot.), a genus of American and Asiatic shrubs
      (Philadelphus), with showy white flowers in panicled
      cymes. Philadelphus coronarius, from Asia, has fragrant
      flowers; the American kinds are nearly scentless.

   Mock sun. See Parhelion.

   Mock turtle soup, a soup made of calf's head, veal, or
      other meat, and condiments, in imitation of green turtle
      soup.

   Mock velvet, a fabric made in imitation of velvet. See
      Mockado.
      [1913 Webster]

WordNet (r) 3.0 (2006):

mock turtle soup
    n 1: soup made from a calf's head or other meat in imitation of
         green turtle soup