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.
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   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.
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