Metamorphism

Part of speech: noun

Pronunciation: /mɛtəˈmɔːfɪz(ə)m/

Definitions

1. The process by which rocks are altered in structure, texture, or composition through exposure to heat, pressure, or chemically active fluids deep within Earth's crust
2. The transformation of one type of rock into another due to changes in temperature, pressure, or chemical processes occurring over geological time
3. A geological alteration process resulting from heat, pressure, and chemically active fluids that change rock types and their properties

Etymology: Metamorphism is a geological term, and its name is built from a Greek word for change. "Metamorphosis" came into English from Greek, combining "meta" (change) with "morphe" (form), and the "-ism" suffix turned that idea into a name for a process. The noun was formed from metamorphosis and -ism, following the French "métamorphisme," so the word was built deliberately as a technical label rather than arising through ordinary speech. The concept it names is a rock changing without melting. Heat, pressure, or chemically active fluids can recrystallize minerals and reorganize a rock's texture while it remains solid. Limestone can become marble, and shale can become slate or schist, all through this process. Because these changes unfold over millions of years, geologists needed a word that described a slow, solid-state transformation distinct from igneous and sedimentary formation.

Synonyms: transformation, change, alteration, conversion, evolution