nitrogen

American  

[nahy-truh-juhn] / ˈnaɪ trə dʒən /

noun

Chemistry.

1. a colorless, odorless, gaseous element that constitutes about four-fifths of the volume of the atmosphere and is present in combined form in animal and vegetable tissues, especially in proteins: used chiefly in the manufacture of ammonia, nitric acid, cyanide, explosives, fertilizer, dyes, as a cooling agent, etc. N; 14.0067; 7; density: 1.2506 grams/liter at 0°C and 760 millimeters pressure.

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nitrogen British  

/ ˈnaɪtrədʒən /

noun

1. 1. a colourless odourless relatively unreactive gaseous element that forms 78 per cent (by volume) of the air, occurs in many compounds, and is an essential constituent of proteins and nucleic acids: used in the manufacture of ammonia and other chemicals and as a refrigerant. Symbol: N; atomic no: 7; atomic wt: 14.00674; valency: 3 or 5; density: 1/ 2506 kg/m³; melting pt: –210.00°C; boiling pt: –195.8°C

   2. ( as modifier )

      nitrogen cycle

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nitrogen Scientific  

/ nī′trə-jən /

1. A nonmetallic element that makes up about 78 percent of the atmosphere by volume, occurring as a colorless, odorless gas. It is a component of all proteins, making it essential for life, and it is also found in various minerals. Nitrogen is used to make ammonia, nitric acid, TNT, and fertilizers. Atomic number 7; atomic weight 14.0067; melting point −209.86°C; boiling point −195.8°C; valence 3, 5.

2. See Periodic Table See Note at oxygen

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nitrogen Cultural  

1. A chemical element that makes up about four-fifths of the atmosphere of the Earth. Its symbol is N.

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Discover More

Like carbon, nitrogen is a necessary element in the tissues of living things.

Etymology

Origin of nitrogen

First recorded in 1785–95; from French nitrogène; see origin at nitro-, -gen

Example Sentences

Nitrogen and urea, a nitrogen derivative, will be most affected in the U.S., since 40% to 45% of urea arrives between March and May each year.

From Barron's • Mar. 12, 2026

Nitrogen dioxide has been associated with adverse health effects including increased respiratory symptoms.

From BBC • Aug. 28, 2025

Nitrogen dioxide, a lung-irritating gas and component of smog, is nearly inescapable as it is produced by the burning of fossil fuels.

From Los Angeles Times • Oct. 5, 2024

Nitrogen is a nutrient essential for all life on Earth.

From Science Daily • Apr. 3, 2024

Nitrogen mustard, after all, is not sprayed upon whole populations from the air; its use is in the hands of experimental biologists or of physicians who use it in cancer therapy.

From "Silent Spring" by Rachel Carson