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

Chemicals such as chlorine gas, bromine vapor, hydrogen chloride, hydrogen bromide, nitrogen trichloride, particulate matter, and other compounds are believed to have been released into the air, the lawsuit alleges. — Irene Wright, USA Today, 23 June 2026

All bodies of stagnant water are particularly vulnerable to a process known as eutrophication (the gradual increase in the concentration of plant nutrients such as phosphorus and nitrogen), and the Reflecting Pool is no exception. — Tracy Grant, Encyclopedia Britannica, 23 June 2026

Farmers participating in the Avalo program exceeded their program requirement of applying less than 30 pounds of nitrogen per acre, going so far as reducing fertilizer usage by 71 percent. — Jennifer Bringle, Footwear News, 22 June 2026

There's no propulsion system, though there are attitude control thrusters using compressed nitrogen gas and a parachute system for reentry. — David Szondy june 22, New Atlas, 22 June 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