Source : Webster's Revised Unabridged Dictionary (1913)

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.

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

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

Fossilize \Fos"sil*ize\, v. i.
   1. To become fossil.

   2. To become antiquated, rigid, or fixed, beyond the
      influence of change or progress.

Source : WordNet®

fossilize
     v 1: convert to a fossil; "The little animals fossilized and are
          now embedded in the limestone" [syn: {fossilise}]
     2: become mentally inflexible [syn: {fossilise}]