monoxide

American  

[mon-ok-sahyd, muh-nok-] / mɒnˈɒk saɪd, məˈnɒk- /

noun

Chemistry.

1. an oxide containing one oxygen atom in each molecule.

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monoxide British  

/ mɒˈnɒksaɪd /

noun

1. an oxide that contains one oxygen atom per molecule

   carbon monoxide, CO

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monoxide Scientific  

/ mə-nŏk′sīd′ /

1. A compound consisting of two elements, one of which is a single oxygen atom. Carbon monoxide, for example, contains a carbon atom bound to a single oxygen atom.

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Etymology

Origin of monoxide

First recorded in 1865–70; mon- + oxide

Example Sentences

A rom-com need not be a sparkling shelf covered with bon-bons, but it shouldn’t be a nauseating cloud of carbon monoxide that makes you want to flee.

From The Wall Street Journal • Apr. 2, 2026

Det Chief Insp Ben Robinson said that although the post-mortem examinations, which were held on Sunday, were yet to establish a cause, carbon monoxide poisoning remained a primary line of inquiry.

From BBC • Feb. 23, 2026

The 2009 endangerment finding was the result of a major report by the EPA, which identified six greenhouse gases, including carbon monoxide and methane, as endangering current and future generations.

From BBC • Feb. 13, 2026

From orbit, scientists can identify chemicals in the upper atmosphere, including ammonia, methane, ammonium hydrosulfide, water, and carbon monoxide.

From Science Daily • Jan. 31, 2026

There are small traces of nitrogen, water vapor, argon, carbon monoxide and other gases, but the only hydrocarbons or carbohydrates present are there in less than 0.1 parts per million.

From "Cosmos" by Carl Sagan