What does oxygen mean?
Oxygen is a colorless, odorless gaseous chemical element that makes up roughly one-fifth of Earth's atmosphere. It is essential to aerobic respiration, allowing animals and many microorganisms to release energy from food, and it also supports the chemical reactions involved in combustion. Consequently, oxygen carries strong associations with breathing, life, energy, and intensity. In hospitals, it is commonly supplied to patients whose breathing or blood-oxygen levels need support, while mountaineers, divers, pilots, and firefighters may use compressed or stored oxygen. The word can also appear figuratively when a person or thing is described as vital to the vitality of a group or activity. Although oxygen itself is invisible, its presence is easy to recognize through the effects of its absence: candles cannot burn, engines cannot run, and most animals cannot survive without it. Its scientific importance and its immediate connection to human life make it one of the most familiar elements in everyday language.
The chemical element with the symbol O, existing as a colorless, odorless gas that supports respiration and combustion.
"The tent was stocked with food, oxygen, and emergency equipment."
Normally uncountable in general use; “oxygens” is a rare scientific countable plural.
To supply with oxygen or treat with oxygen.
"The system oxygens the water before circulating it through the reactor."
Chiefly British and used mainly in technical contexts.
Rare and specialized; oxygen is ordinarily used as an uncountable noun.
"Each water molecule contains two oxygens."
Its name literally means “acid-producer,” an early chemical guess that was later found to be misleading.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does oxygen come from?
The word oxygen was formed in the late eighteenth century from Greek roots meaning “sharp” or “acid” and “producing.” Antoine Lavoisier and his colleagues adopted it for the substance then believed to be the acid-producing principle associated with combustion. The name was ultimately misleading, but it remained established and gave rise to related terms such as oxide, oxidation, and oxidize.
Related word forms
How oxygen is actually used
Oxygen is normally an uncountable mass noun; a rare countable plural is used in specialized scientific contexts. In medical settings, “on oxygen” means receiving supplemental oxygen. As a verb, oxygen is chiefly a British technical term meaning to supply or treat with oxygen.
Easily confused with oxygen
Oxygen is a chemical element and gas, whereas an oxide is a compound formed when oxygen combines with another element.