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

Avoid root disturbance when transplanting, under or over-watering, overcrowding, intense heat and sun, and too much nitrogen in fertilizers. — Gemma Johnstone, The Spruce, 2 July 2026

Avoid Fertilizing Avoid high-nitrogen fertilizer during periods of high heat or drought. — Martha Stewart, 2 July 2026

Hypoxia in the Long Island Sound, which usually occurs in the summer, is when bottom water oxygen levels fall to a critical low percentage due to nitrogen from water runoff and backyard fertilizer use. — Stephen Underwood, Hartford Courant, 29 June 2026

Next to seemingly endless rows of bell peppers, sweet corn and leafy greens at B & T Farms stand thousand-gallon drums of nitrogen fertilizer, the cost of which has increased 125% since 2020 amid supply shocks and wars around the world. — Chase Hunter, Mercury News, 28 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