The Collaborative International Dictionary of English v.0.48:

Fossilize \Fos"sil*ize\, v. t. [imp. & p. p. Fossilized; p.
   pr. & vb. n. Fossilizing.] [Cf. F. fossiliser.]
   1. To convert into a fossil; to petrify; as, to fossilize
      bones or wood.
      [1913 Webster]

   2. To cause to become antiquated, rigid, or fixed, as by
      fossilization; to mummify; to deaden.
      [1913 Webster]

            Ten layers of birthdays on a woman's head
            Are apt to fossilize her girlish mirth. --Mrs.
                                                  Browning.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fossilized \Fos"sil*ized\, a.
   Converted into a fossil; antiquated; firmly fixed in views or
   opinions.
   [1913 Webster]

         A fossilized sample of confused provincialism. --Earle.
   [1913 Webster]

WordNet (r) 3.0 (2006):

fossilized
    adj 1: set in a rigidly conventional pattern of behavior,
           habits, or beliefs; "obsolete fossilized ways"; "an
           ossified bureaucratic system" [syn: fossilized,
           fossilised, ossified]