oxygen

[ ok-si-juhn ]

/ ˈɒk sɪ dʒən /

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noun Chemistry.

a colorless, odorless, gaseous element constituting about one-fifth of the volume of the atmosphere and present in a combined state in nature. It is the supporter of combustion in air and was the standard of atomic, combining, and molecular weights until 1961, when carbon 12 became the new standard. Symbol: O; atomic weight: 15.9994; atomic number: 8; density: 1.4290 grams/liter at 0°C and 760 millimeter pressure.

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Origin of oxygen

First recorded in 1780–90; from French oxygène, equivalent to oxy- + -gène; see origin at oxy-¹, -gen

OTHER WORDS FROM oxygen

ox·y·gen·ic

[ok-si-jen-ik], /ˌɒk sɪˈdʒɛn ɪk/, ox·yg·e·nous

[ok-sij-uh-nuhs], /ɒkˈsɪdʒ ə nəs/, adjectiveox·y·gen·ic·i·ty

[ok-si-juh-nis-i-tee], /ˌɒk sɪ dʒəˈnɪs ɪ ti/, noun

Words nearby oxygen

oxychromatic, oxycodone, oxycodone hydrochloride, OxyContin, oxyesthesia, oxygen, oxygen acid, oxygen affinity hypoxia, oxygenase, oxygenate, oxygenated hemoglobin

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use oxygen in a sentence

Most carbohydrates have the same oxygen to hydrogen ratio as water.
Scientists Say: Carbohydrate|Bethany Brookshire|August 24, 2020|Science News For Students
Her aunt eventually recovered, was taken off a ventilator and is home, though she still needs oxygen.
Coronavirus Hit Latinos Harder Thanks to a Perfect Storm of Disparities|Maya Srikrishnan|August 12, 2020|Voice of San Diego
Photosynthetic cyanobacteria that arose some 3 billion years ago, for instance, began terraforming the planet by emitting oxygen.
How Earth’s Climate Changes Naturally (and Why Things Are Different Now)|Howard Lee|July 21, 2020|Quanta Magazine
Researchers found no benefit for hospitalized patients who didn’t need extra oxygen.
The steroid dexamethasone is the first drug shown to reduce COVID-19 deaths|Tina Hesman Saey|June 16, 2020|Science News

So extra oxygen in the atmosphere may have provided the conditions for large insects to evolve.
Minecraft’s big bees don’t exist, but giant insects once did|Carolyn Wilke|May 14, 2020|Science News For Students
The others are difficult to identify, since they reacted with other oxygen-bearing molecules in the soil.
Methane on Mars: Life or Just Gas?|Matthew R. Francis|December 17, 2014|DAILY BEAST
It reacts very readily with oxygen by burning smokelessly, with carbon dioxide and water as its byproducts.
Methane on Mars: Life or Just Gas?|Matthew R. Francis|December 17, 2014|DAILY BEAST
Their decay proceeded without a ready supply of oxygen, producing hydrocarbons like methane instead of oxygen-bearing molecules.
Methane on Mars: Life or Just Gas?|Matthew R. Francis|December 17, 2014|DAILY BEAST
As the heart pumps blood to the far reaches of the body, it requires its own blood flow to receive vital oxygen and nutrients.
Justice Ruth Bader Ginsburg’s Risky Heart Surgery|Dr. Anand Veeravagu, MD|November 26, 2014|DAILY BEAST
The brain, also an organ, is particularly sensitive to the loss of oxygen.
What It’s Like to Wake Up Dead|Dr. Anand Veeravagu, MD, Tej Azad|November 21, 2014|DAILY BEAST
In the lungs hemoglobin forms a loose combination with oxygen, which it readily gives up when it reaches the tissues.
A Manual of Clinical Diagnosis|James Campbell Todd
They are cells which have been highly differentiated for the purpose of carrying oxygen from the lungs to the tissues.
A Manual of Clinical Diagnosis|James Campbell Todd
Its most important compound is water, of which it forms one-ninth, the other eight-ninths consisting of oxygen.
Elements of Agricultural Chemistry|Thomas Anderson
In the flowers, both by day and night, there is a constant absorption of oxygen, and evolution of carbonic acid.
Elements of Agricultural Chemistry|Thomas Anderson
In the first case, the oil rapidly combines with the oxygen of the air, this being accompanied by great heat.
The Wonder Book of Knowledge|Various

British Dictionary definitions for oxygen

oxygen

/ (ˈɒksɪdʒən) /

noun

a colourless odourless highly reactive gaseous element: the most abundant element in the earth's crust (49.2 per cent). It is essential for aerobic respiration and almost all combustion and is widely used in industry. Symbol: O; atomic no: 8; atomic wt: 15.9994; valency: 2; density: 1.429 kg/m³; melting pt: –218.79°C; boiling pt: –182.97°C
(as modifier)an oxygen mask

Derived forms of oxygen

oxygenic (ˌɒksɪˈdʒɛnɪk) or oxygenous (ɒkˈsɪdʒɪnəs), adjective

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for oxygen

oxygen

[ ŏk′sĭ-jən ]

n. Symbol O

An element constituting 21 percent of the atmosphere by volume that occurs as a diatomic gas, O2, combines with most elements, is essential for plant and animal respiration, and is required for nearly all combustion. Atomic number 8.

A medicinal gas used therapeutically for oxygen supplementation, containing not less than 99.0 percent, by volume, of O2.

Scientific definitions for oxygen

oxygen

[ ŏk′sĭ-jən ]

A nonmetallic element that exists in its free form as a colorless, odorless gas and makes up about 21 percent of the Earth's atmosphere. It is the most abundant element in the Earth's crust and occurs in many compounds, including water, carbon dioxide, and iron ore. Oxygen combines with most elements, is required for combustion, and is essential for life in most organisms. Atomic number 8; atomic weight 15.9994; melting point -218.8°C; boiling point -182.9°C; gas density at 0°C 1.429 grams per liter; valence 2. See Periodic Table.

Word History

In 1786, the French chemist Antoine Lavoisier coined a term for the element oxygen (oxygène in French). He used Greek words for the coinage: oxy- means sharp, and -gen means producing. Oxygen was called the sharp-producing element because it was thought to be essential for making acids. Lavoisier also coined the name of the element hydrogen, the water-producing element, in 1788. Soon after, in 1791, another French chemist, J. A. Chaptal, introduced the word nitrogen, the niter-producing element, referring to its discovery from an analysis of nitric acid.

Cultural definitions for oxygen

oxygen

An element, normally a gas, that makes up about one-fifth of the atmosphere of the Earth. Oxygen is usually found as a molecule made up of two atoms. Its symbol is O.

notes for oxygen

When we breathe in oxygen, it is carried by the hemoglobin in our blood throughout the body, where it is used to generate energy by oxidation. (See respiration.)

notes for oxygen

Oxygen is a waste product of green plants and photosynthesis.