nitrogen

American  

[nahy-truh-juhn] / ˈnaɪ trə dʒən /

noun

Chemistry.

nitrogens plural

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.

Other Word Forms

Noun Inflected Forms

• nitrogens
  plural

Etymology

Origin of nitrogen

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

Example Sentences

This software recognised when cars were undergoing official emissions tests, and turned on systems designed to reduce their output of nitrogen dioxide, a gas which can cause respiratory problems.

From BBC • Jul. 10, 2026

It will produce liquid ammonia—a chemical widely used in fertilizer—from hydrogen and nitrogen gases.

From The Wall Street Journal • Jul. 2, 2026

The answer, for that sample, was: mostly Desmodesmus, a green algae that gobbles up phosphorus and nitrogen.

From Slate • Jun. 27, 2026

The approach relies on a diamond containing a microscopic magnetic defect formed by a nitrogen atom and a missing neighboring carbon atom.

From Science Daily • Jun. 23, 2026

The nitrogen for the fields would no longer be made with the sun’s energy but with fossil fuels.

From "The Omnivore's Dilemma" by Michael Pollan