oxygen

ox-y-gen · noun

imported

Definitions

noun

  1. 1.

    A colorless, odorless gas that is essential for respiration and combustion, constituting about 21 percent of the Earth's atmosphere.

  2. 2.

    A chemical element with the symbol O and atomic number 8, existing as a diatomic molecule in its most common form.

Phrases & expressions

  • •
    oxygen mask — a device worn over the nose and mouth to supply oxygen
  • •
    oxygen tank — a container holding compressed oxygen for breathing
  • •
    oxygen bar — a venue where customers can breathe purified oxygen

Related words

See also: air, carbon_dioxide, nitrogen, respiration
Synonyms: O2

Etymology

From French oxygène, coined in 1777 by chemist Antoine Lavoisier from Greek oxus ("sharp, acid") + -genēs ("producing"), as oxygen was originally thought to be essential for forming acids.