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
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Sooner or later, the upwelling water and escaping gas will produce a limnic eruption, the violent explosion of tons of carbon dioxide and water into the air. Literary Hub, 22 Oct. 2025 Trees and plants absorb and store a massive amount of carbon dioxide from the air, and in return, through photosynthesis, produce oxygen upon which all life on earth depends. Lauren Liebhaber, Miami Herald, 20 Oct. 2025 By measuring the amount of carbon dioxide in the breath, the Warsaw researchers determined that metabolic rates decreased by as much as forty per cent; heart rates, blood pressure, and core temperature fell. Clayton Dalton, New Yorker, 18 Oct. 2025 By replacing natural gas with the solar and battery system, the oil company avoids 13,000 tons of carbon dioxide emissions annually while also lowering costs, according to the battery startup’s founder and Chief Innovation Officer John O’Donnell. Bloomberg, Mercury News, 16 Oct. 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

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Cite this Entry

“Carbon dioxide.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/carbon%20dioxide. Accessed 24 Oct. 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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