oxygen

noun, often attributive ox·y·gen \ ˈäk-si-jən \

|Updated on: 18 Jun 2018

Definition of oxygen

1 : a reactive element that is found in water, in most rocks and minerals, in numerous organic compounds, and as a colorless tasteless odorless diatomic gas constituting 21 percent of the atmosphere, that is capable of combining with all elements except the inert gases, that is active in physiological processes, and that is involved especially in combustion — see Chemical Elements Table

2 : something that sustains or fuels

disagreement is the true oxygen of these magazines
—Joseph Epstein

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oxygenless

play \ˈäk-si-jən-ləs\ adjective

See oxygen defined for English-language learners

See oxygen defined for kids

Recent Examples of oxygen from the Web

With its ability to produce oxygen and drinking water from the ocean, the Hartford has the ability to stay out to sea for weeks or months on end.

— frank vaisvilas, Lake County News-Sun, "From Grayslake to the North Pole: Lake County native describes service aboard submarine," 7 June 2018
The placenta is a unique organ made up of fetal and maternal tissue that helps deliver nutrients and oxygen to the fetus during pregnancy and remove waste products.

— mark lieber, CNN, "Pregnancy complications might 'turn on' schizophrenia genes, study says," 30 May 2018
The water out here is between 90 and 120 feet deep, so the divers breathe nitrox from their tanks, a cocktail of nitrogen and oxygen that allows them to make safer trips up and down and stay a little longer on the bottom.

— ben lowy, Smithsonian, "The Lionfish Have Invaded, But a Ragtag Army of Divers and Chefs Are Fighting Back," 23 May 2018
By the time the helicopter came, the team had run out of reserve oxygen and Pozdnii had frostbite on his hands and feet.

— ash routen, Outside Online, "A Climber Left $50,000 on the Top of Everest," 23 May 2018
Many South Florida slash pines have stood for a century, providing shade, oxygen and wildlife habitat, as cities rose around them.

— david fleshler, Sun-Sentinel.com, "Asian termites killing South Florida pine trees, weakening other trees for hurricanes," 14 Apr. 2018
Her two favorites: Skin Thesis’ Runway Facial (incorporating laser, oxygen and LED facials) and a radio frequency facial, which all together cost up to $1,500 per visit.

— kaitlyn frey, PEOPLE.com, "Kim Kardashian's Go-To Skin Care Expert Reveals What Really Goes on During Their 10 PM Facials," 4 Apr. 2018
The others are carbon, hydrogen, nitrogen, oxygen and sulphur.

— jay bennett, Popular Mechanics, "To Find Life in Our Galaxy, Follow the Phosphorus," 4 Apr. 2018
Carbon, oxygen and hydrogen are also important nutrients and come to plants via air and water.

— amy hall, sandiegouniontribune.com, "Growing season ahead depends on proper feeding," 7 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'oxygen.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of oxygen

French oxygène, from Greek oxys, adjective, acidic, literally, sharp + French -gène -gen; akin to Latin acer sharp — more at edge

NEW! Time Traveler

First Known Use: 1788

in the meaning defined at sense 1

See Words from the same year

Other Chemical Engineering Terms

alkali, cation, decant, hygroscopic, isotope, oxidize, slurry, solute, viscous

OXYGEN Defined for English Language Learners

oxygen

noun

Definition of oxygen for English Language Learners

: a chemical that is found in the air, that has no color, taste, or smell, and that is necessary for life

OXYGEN Defined for Kids

oxygen

noun ox·y·gen \ ˈäk-si-jən \

Definition of oxygen for Students

: a chemical element found in the air as a colorless odorless tasteless gas that is necessary for life

History for oxygen

People once thought that all acids were formed by adding oxygen to some other substance. This belief turned out not to be true. However, it did give oxygen its name. The first part of the word, oxy-, came from Greek oxys, meaning “acid” or “sharp.” The second part, -gen, came from a Greek element meaning “producing” or “giving rise to.”

Medical Dictionary

oxygen

noun ox·y·gen \ ˈäk-si-jən \

medical Definition of oxygen

: a colorless tasteless odorless gaseous element that constitutes 21 percent of the atmosphere and is found in water, in most rocks and minerals, and in numerous organic compounds, that is capable of combining with all elements except the inert gases, that is active in physiological processes, and that is involved especially in combustion processes —symbol O — see Chemical Elements Table

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