oxygen
UK /ˈɒksɪd͡ʒən/ · US /ˈɑksɪd͡ʒən/ noun
Forms oxygens
- noun (chemistry) The chemical element (symbol O) with an atomic number of 8 and relative atomic mass of 15.9994. It is a colorless and odorless gas. Sometimes called elemental oxygen to distinguish it from molecular oxygen. “By molar fraction, calcium oxide contains equal parts calcium and oxygen.”
- noun (loose but very common, even in formal use) Molecular oxygen (O₂), a colorless, odorless gas at room temperature. “About 21% of the air you breathe is oxygen.”
- noun (medicine) A mixture of oxygen and other gases, administered to a patient to help them breathe.
- noun (countable) An atom of this element.
- noun (figurative) A condition or environment in which something can thrive. “Silence is the oxygen of shame.”
Synonyms
sourstuff E948[packaging gas]]> dioxygen mul:O₂ O atomic number 8
Etymology
Borrowed from French oxygène (originally in the form principe oxygène, a variant of principe oxigine ‘acidifying principle’, suggested by Lavoisier), from Ancient Greek ὀξύς (oxús, “sharp”) + γένος (génos, “birth”), referring to oxygen's supposed role in the formation of acids. By surface analysis, oxy- + -gen.
Webster’s 1913
- A colorless, tasteless, odorless, gaseous element occurring in the free state in the atmosphere, of which it forms about 23 per cent by weight and about 21 per cent by volume, being slightly heavier than nitrogen. Symbol O. Atomic weight 15.96.
- Chlorine used in bleaching. [Manufacturing name]
Etymology [F. oxygène, from Gr. acid.]
Sources: Wiktionary · WordNet 3.0 · Webster’s 1913 — from the Wiktionary entry “oxygen”, CC BY-SA 4.0. Details