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

Between the shortages and legal challenges over botched executions, some states have moved to alternative methods of execution, including firing squads in South Carolina and nitrogen gas in Alabama. —CBS News, 11 Dec. 2025

Coffee grounds contain carbon, nitrogen, and trace minerals that feed soil microbes that promote good soil structure and improve drainage. —Mary Marlowe Leverette, Southern Living, 10 Dec. 2025

According to Farm Action’s Agriculture Consolidation Data Hub, three fertilizer companies (CF Industries, Nutrien, and Koch) control 93% of North American nitrogen fertilizer sales in North America. —Sasha Rogelberg, Fortune, 9 Dec. 2025

The oxygen and nitrogen molecules also emit ultraviolet light, which can only be detected by special cameras on satellites. —Jenna Prestininzi, Freep.com, 8 Dec. 2025

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