The Collaborative International Dictionary of English v.0.48:

Carbonization \Car`bon*i*za"tion\, n. [Cf. F. carbonisation.]
   1. The act or process of carbonizing.
      [1913 Webster]

   2. the destructive distillation of coal (as in coke ovens).

   Syn: carbonisation.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

carbonization
    n 1: the destructive distillation of coal (as in coke ovens)
         [syn: carbonization, carbonisation]