noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   The old geological theory that the rocks forming the Earth were formed in fire by volcanic activity, with a continuing gradual process of weathering and erosion, then deposited on the sea bed, re-formed into layers of sedimentary rock by heat and pressure, and raised again. countable, uncountable
2. 2
   Alternative letter-case form of plutonism. alt-of, uncountable

Synonyms

All synonyms

vulcanismvulcanism

Etymology

From Pluto + -ism, after the classical ruler of the underworld.

Related phrases

sedimentary rock

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.