oxygen

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

Updated on: 24 Apr 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

Blood vessels in the extremities also constrict, channeling oxygen-rich blood to vital organs.

— michael nedelman, CNN, "Diving deep on one breath could be in a 'sea nomad's' DNA," 19 Apr. 2018
Scientists suspect the mutation alters the spleen, a part of the body that’s instrumental in maintaining body functions with limited oxygen.

— jared gilmour, miamiherald, "Human 'sea nomads' can dive up to 13 minutes — thanks to this DNA mutation, study finds | Miami Herald," 19 Apr. 2018
Tethered to oxygen, the Chrysler employee had suffered from a disease called idiopathic pulmonary fibrosis for the past seven years.

— shari rudavsky, Indianapolis Star, "The opioid crisis ‘silver lining’: A heroin overdose that killed 1 mom, saved 4 lives," 19 Apr. 2018
Their secret is an oxygen-carrying compound called heme, which makes blood appear red and makes meat taste, well, meaty.

— alison roman, WSJ, "Plant-Based ‘Meat’ and ‘Fish’ May Be the Future. But How Do They Taste?," 12 Apr. 2018
In a heart attack, the oxygen-carrying blood supply to the heart is cut off, and those cells begin to die 40 minutes later.

— elizabeth cooney, STAT, "Rebuilding dying hearts: Meet the STAT Madness 2018 crowd favorite," 2 Apr. 2018
With nitrogen hypoxia, death would occur from breathing only nitrogen, without the life-sustaining oxygen that makes up about 20 percent of the air.

— mike cason, AL.com, "Alabama's new method of execution has never been tried," 26 Mar. 2018
At the other, the lithium reacts with oxygen in the air.

— john timmer, Ars Technica, "New lithium-air battery survives hundreds of cycles," 22 Mar. 2018
The best-selling author and star of IMAX's Everest Expedition documentary has summited all 14 of the world's tallest peaks—including Everest, without oxygen—and is widely regarded as America's foremost authority on mountaineering.

— nate erickson, Esquire, "A Pro Mountain Climber Told Us He Could Climb Trump's Border Wall," 13 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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