Geology . to convert into a fossil; replace organic with mineral substances in the remains of an organism.

to change as if into mere lifeless remains or traces of the past.

to make rigidly antiquated

Time has fossilized such methods.

to become a fossil or fossillike

The plant fossilized in comparatively recent geologic time.

Linguistics . (of a linguistic form, feature, rule, etc.) to become permanently established in the interlanguage of a second-language learner in a form that is deviant from the target-language norm and that continues to appear in performance regardless of further exposure to the target language.