carbon monoxide

noun

: a colorless odorless very toxic gas CO that is formed as a product of the incomplete combustion of carbon or a carbon compound

Examples of carbon monoxide in a Sentence

Recent Examples on the Web

The medical examiner’s office previously said that foul play was not suspected, but that carbon monoxide poisoning has been ruled out as a possibility. — Justin Muszynski, Hartford Courant, 25 Aug. 2026

Again, an idling engine still emits exhaust gases such as carbon monoxide, nitrogen oxides, and hydrocarbons, and these emissions will ultimately end up in the air and contribute to air pollution. — Molly Burford, Southern Living, 22 Aug. 2026

With many people using generators, poor ventilation can lead to carbon monoxide poisoning. — ABC News, 20 Aug. 2026

The streamer is composed mostly of molecular hydrogen, but since molecular hydrogen is invisible at radio wavelengths, ALMA searched for molecules of carbon monoxide in the streamer instead. — Keith Cooper, Space.com, 17 Aug. 2026

Word History

First Known Use

1868, in the meaning defined above

Rhymes for carbon monoxide

• hydroxide
• tetroxide

Kids Definition

carbon monoxide

noun

: a colorless odorless very poisonous gas formed by the incomplete burning of carbon

Medical Definition

carbon monoxide

noun

: a colorless odorless very toxic gas CO that burns to carbon dioxide with a blue flame and is formed as a product of the incomplete combustion of carbon