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

Your Blood Pressure and Cholesterol May Improve Pickled beets contain nitrates, which are naturally occurring nitrogen and oxygen compounds. —Angelica Bottaro, Verywell Health, 29 Jan. 2026

The new electrode can operate efficiently in mixed gases similar to those found in industrial flue emissions, including nitrogen and oxygen. —Neetika Walter, Interesting Engineering, 29 Jan. 2026

Katharine’s research on harmless oxygen and nitrogen, the main components of air, paved the way for two vital advances for filter design. —Natalia Sánchez Loayza, Scientific American, 29 Jan. 2026

While the Launch 11 style isn’t on the list, it’s made with Brooks’ proprietary DNA Flash foam cushioning, which is infused with nitrogen for higher-energy returns and responsive support. —Stephanie Osmanski, Better Homes & Gardens, 28 Jan. 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