The Collaborative International Dictionary of English v.0.48:

Freezing \Freez"ing\, a.
   Tending to freeze; for freezing; hence, cold or distant in
   manner. -- Frrez"ing*ly, adv.
   [1913 Webster]

   Freezing machine. See Ice machine, under Ice.

   Freezing mixture, a mixture (of salt and snow or of
      chemical salts) for producing intense cold.

   Freezing point, that degree of a thermometer at which a
      fluid begins to freeze; -- applied particularly to water,
      whose freezing point is at 32[deg] Fahr., and at 0[deg]
      Centigrade.
      [1913 Webster]

WordNet (r) 3.0 (2006):

freezing mixture
    n 1: a mixture of substances (usually salt and ice) to obtain a
         temperature below the freezing point of water