carbon dioxide

noun

: a heavy colorless gas CO2 that does not support combustion, dissolves in water to form carbonic acid, is formed especially in animal respiration and in the decay or combustion of animal and vegetable matter, is absorbed from the air by plants in photosynthesis, and is used in the carbonation of beverages

Examples of carbon dioxide in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The Biden administration had calculated that an end to federal coal sales would reduce emissions by the equivalent of 293 million tons (266 million metric tonnes) of carbon dioxide annually. Sydney Lake, Fortune, 8 July 2025 On Earth, where tectonic activity constantly exposes fresh rock to the atmosphere, carbonate minerals like limestone form when rock reacts with water and carbon dioxide (CO2). Victoria Corless, Space.com, 4 July 2025 Why Big Tech and Big Oil Are Betting on Carbon Capture According to a 2024 Newsweek report, tech giants like Microsoft, Alphabet, Meta, and Salesforce are aggressively investing in carbon dioxide removal technologies to meet their net-zero targets and hedge against future climate risks. Dianne Plummer, Forbes.com, 4 July 2025 Even in those earliest of gloomy days, oxygen — the element O — was all over the place, bound up in molecules like water vapor and quartz and carbon dioxide. Laura Poppick, Rolling Stone, 30 June 2025 See All Example Sentences for carbon dioxide

Word History

First Known Use

1867, in the meaning defined above

Time Traveler
The first known use of carbon dioxide was in 1867

Browse Nearby Words

Cite this Entry

“Carbon dioxide.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/carbon%20dioxide. Accessed 16 Jul. 2025.

Kids Definition

carbon dioxide

noun
: a heavy colorless gas CO2 that is formed especially by the burning and breaking down of organic substances (as in animal respiration), is absorbed from the air by plants in photosynthesis, and has many industrial uses

Medical Definition

carbon dioxide

noun
: a heavy colorless gas CO2 that does not support combustion, dissolves in water to form carbonic acid, is formed especially in animal respiration and in the decay or combustion of animal and vegetable matter, is absorbed from the air by plants in photosynthesis, and is used in the carbonation of beverages

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