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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
Federal lawsuits are challenging the California waiver used to support Maryland’s regulation and the Environmental Protection Agency’s effort to regulate vehicles based on carbon dioxide emissions that Congress has not approved.
—David T. Stevenson, Baltimore Sun, 22 Jan. 2025
Two years later, under former President Barack Obama, the E.P.A. concluded that six greenhouse gases, including carbon dioxide and methane, are a threat to human health and welfare, and must be regulated under the Clean Air Act.
—Lisa Friedman, New York Times, 21 Jan. 2025
Burning fossil fuels like gasoline and diesel release carbon dioxide, a greenhouse gas, into the environment.
—Andrew J. Hawkins, The Verge, 21 Jan. 2025
While some carbonated water is natural, created as volcanic gases infuse the water in natural springs with bubbles and minerals, most sparkling water is made by forcing carbon dioxide, or CO2, into water under intense pressure.
—Sandee Lamotte, CNN, 21 Jan. 2025
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Word History
First Known Use
1867, in the meaning defined above
Dictionary Entries Near carbon dioxide
Cite this Entry
“Carbon dioxide.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/carbon%20dioxide. Accessed 27 Jan. 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
More from Merriam-Webster on carbon dioxide
Britannica.com: Encyclopedia article about carbon dioxide
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