Fossilization may refer to
- Fossilization (palaeontology): The set of geological processes that convert organic remains into fossils.
- Fossilization (language acquisition): loss of progress in second language acquisition, where learners no longer move towards native-like ability in the second language, often despite constant exposure to it.
- Cranberry word: or 'fossilized term', used in morphology to refer to exceptional compound words not built from productive rules, e.g. cranberry (no such thing as *cran-).