nitrous oxide

American  

noun

Chemistry, Pharmacology.

• nitrous oxides
  plural

1. a colorless, sweet-smelling, sweet-tasting, nonflammable, slightly water-soluble gas, N 2 O, that sometimes produces a feeling of exhilaration when inhaled: used chiefly as an anesthetic in dentistry and surgery, in the manufacture of chemicals, and as an aerosol.

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nitrous oxide British  

noun

1. Systematic name: dinitrogen oxide.  Also called: laughing gas.  a colourless nonflammable slightly soluble gas with a sweet smell: used as an anaesthetic in dentistry and surgery. Formula: N 2 O

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nitrous oxide Scientific  

1. A colorless, sweet-smelling gas. It is used as a mild anesthetic, often called laughing gas. Nitrous oxide occurs naturally in the atmosphere and is a greenhouse gas. Chemical formula: N ₂ O.

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Other Word Forms

Noun Inflected Forms

• nitrous oxides
  plural

Etymology

Origin of nitrous oxide

First recorded in 1790–1800

Example Sentences

See Examples For:

nitrous oxide

That nitrous oxide could have helped early Earth retain heat.

From Science Daily ● Sep. 2, 2026

The smaller surviving amount of nitrous oxide could have supported prebiotic chemical reactions.

From Science Daily ● Sep. 2, 2026

A 2024 report by the United Nations Environment Programme and the Food and Agriculture Organization warned that rising nitrous oxide emissions linked to fertiliser use are threatening climate goals.

From Barron's ● Jun. 16, 2026

Banned items include weapons, fireworks, flares, gas canisters, laser pens, camping chairs, umbrellas, flagpoles, air horns, megaphones, nitrous oxide, and excessive food and cigarettes security would think was more than "personal use".

From BBC ● Jun. 10, 2026

Some of it turns into nitrous oxide, a gas that increases global warming.

From "The Omnivore's Dilemma" by Michael Pollan