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

Corteva supplies farmers with products for pest and disease control, as well as seeds, livestock feed and nutrient maximizers, which help stabilize nitrogen levels in the soil. —Brett Owens, Forbes.com, 15 May 2025

Chickweed thrives in neutral pH soil with high nitrogen. —Megan Hughes, Better Homes & Gardens, 8 May 2025

The most common method involves very rapidly freezing plant tissue to ultra-low temperatures—usually by placing it in liquid nitrogen below minus 238 degrees Fahrenheit—so ice crystals don’t have time to form. —Katarina Zimmer, Smithsonian Magazine, 2 May 2025

Pollutants from water treatment plants and septic tanks on the edge of the lagoon have slowly leaked nitrogen and phosphorus into the water, one expert said. —Jade Walker, CNN Money, 1 May 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