The Collaborative International Dictionary of English v.0.48:

Fossilization \Fos`sil*i*za"tion\, n. [Cf. F. fossilisation.]
   The process of converting, or of being converted, into a
   fossil.
   [1913 Webster]

WordNet (r) 3.0 (2006):

fossilization
    n 1: the process of fossilizing a plant or animal that existed
         in some earlier age; the process of being turned to stone
         [syn: fossilization, fossilisation]
    2: becoming inflexible or out of date [syn: fossilization,
       fossilisation]