noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   The region of the Earth's atmosphere (from 20 to 120 miles above the surface) in which photochemical reactions take place.

Synonyms

All synonyms

beltionospherelayerstratospherestratumtroposphere

Etymology

From chemo- + -sphere.

Related phrases

ozone layer

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