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 elevated helium and argon signals were accompanied by no corresponding rise in nitrogen, which the study said provided evidence against atmospheric leakage being the sole explanation. — Neetika Walter, Interesting Engineering, 22 Sep. 2026

Kia does not specifically recommend nitrogen tire inflation, transmission flushing, or fuel induction cleaning as part of the normal maintenance schedule. — John Paul Senior Manager Public Affairs and Traffic Safety Aaa Northeast, Hartford Courant, 19 Sep. 2026

For coffee grounds to release their nitrogen, phosphorus, and potassium, they must first be processed by soil microbes. — Leanne Potts, Better Homes & Gardens, 19 Sep. 2026

Salk scientists think longer, bigger roots could also absorb more nitrogen and other fertilizer runoff, which can cause algae blooms and lead to low-oxygen environments that kill marine life. — ABC News, 18 Sep. 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