nitrogen

noun

ni·​tro·​gen ˈnī-trə-jən 

: a nonmetallic chemical element with atomic number 7 that under standard conditions is a colorless, odorless, inert gas, that constitutes 78 percent of the Earth's atmosphere, and that is used especially in the industrial synthesis of ammonia, as a component of inert atmospheres, and in liquid form as a refrigerant

—often used before another noun

the nitrogen cycle

nitrogen fertilizer

see Chemical Elements Table

Examples of nitrogen in a Sentence

Recent Examples on the Web

The plant will feed on renewable power from Paraguay’s vast Itaipu dam to produce hydrogen by splitting water through electrolysis, which is then combined with nitrogen to create zero-carbon ammonia. —Natasha Bracken, semafor.com, 28 Apr. 2026

This public company with $7 billion in sales last year is a leading global supplier of anhydrous ammonia, a building block of nitrogen fertilizers. —The Editorial Board, Chicago Tribune, 27 Apr. 2026

Conflict in the Middle East is rattling energy markets, pushing up the cost of natural gas—the backbone of nitrogen fertilizer production—and exposing once again just how vulnerable farmers and families are to shocks beyond their control. —Carlos Alvarado Quesada, Fortune, 27 Apr. 2026

Cotton linters—the short fibers left on cottonseed after ginning—can be processed into nitrocellulose, a highly volatile, nitrogen-rich material known as guncotton that’s used as a primary ingredient in solid rocket propellants for ballistic missiles. —Jasmin Malik Chua, Footwear News, 27 Apr. 2026

Word History

Etymology

French nitrogène, from nitre niter + -gène -gen

First Known Use

1791, in the meaning defined above

Phrases Containing nitrogen

• nitrogen balance
• nitrogen cycle
• nitrogen dioxide
• nitrogen fixation
• nitrogen-fixer
• nitrogen-fixing
• nitrogen mustard
• nitrogen narcosis
• nitrogen oxide
• nitrogen tetroxide

Kids Definition

nitrogen

noun

ni·​tro·​gen ˈnī-trə-jən 

: a colorless tasteless odorless element that occurs as a gas which makes up 78 percent of the atmosphere and that forms a part of all living tissues see element

nitrogenous

nī-ˈträj-ə-nəs 

adjective

Medical Definition

nitrogen

noun

ni·​tro·​gen ˈnī-trə-jən 

: a common nonmetallic element that in the free form is normally a colorless odorless tasteless insoluble inert diatomic gas comprising 78 percent of the atmosphere by volume and that in the combined form is a constituent of biologically important compounds (as proteins, nucleic acids, and alkaloids) and hence of all living cells as well as of industrially important substances (as cyanides, fertilizers, dyes, and antibiotics)

—symbol N see Chemical Elements Table