noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   an allotrope of oxygen having four atoms in each molecule instead of the normal two; only stable under very high pressures

Synonyms

All synonyms

red oxygenred oxygen

Etymology

From tetra- + oxygen.

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