noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   A cycle in rock formation whose major forces come from outside the formation via tectonics, volcanism, climate change, or other outside forces, as contrasted with being contained within the formation.

Etymology

From allo- + cycle, coined by geologists.

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