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 carbon isotopes are found on 3I/ATLAS in compounds such as carbon monoxide and carbon dioxide, and even organic molecules such as methanol, formaldehyde and methane. —Keith Cooper, Space.com, 30 Mar. 2026

The office said that toxicology testing, including carbon monoxide levels, is pending. —Dylan Olsen, CBS News, 23 Mar. 2026

Methane, carbon monoxide, particulate matter in the air and water all have real consequences to our health and 48 others states (like California, Washington, and Colorado) have a sound path towards reduction that New York should follow as well. —New York Daily News Editorial Board, New York Daily News, 22 Mar. 2026

Costa Rican authorities blamed carbon monoxide poisoning. —ABC News, 20 Mar. 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