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

What makes kratom psychoactive are its alkaloids, which naturally occur in many flowering plants, contain nitrogen and have pronounced physiological effects on humans. — Kristen Rogers, CNN Money, 3 Oct. 2026

To convey the brutality of the method, activists tend to bring up the counsel of the World Society for the Protection of Animals, which has advised that nitrogen hypoxia is not fit to put down any mammal. — Doreen St. Félix, New Yorker, 3 Oct. 2026

In most cases, Linde provides oxygen, nitrogen, hydrogen, and helium to customers through merchant sale of gas (SOG) agreements, which is where Linde continually supplies gas to customers through long-term contracts. — Jeff Marks, CNBC, 2 Oct. 2026

Pivot Bio puts cotton in the nitrogen equation Pivot Bio is making its case for replacing some of cotton’s synthetic nitrogen fertilizer with crop nutrition technology that delivers nitrogen to plant roots. — Alexandra Harrell, Footwear News, 2 Oct. 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