Carbon Dioxide Definition & Meaning

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Synonyms carbon dioxide American [kahr-buhn dahy-ok-sahyd] / ˈkɑr bən daɪˈɒk saɪd /

noun

1. a colorless, odorless, incombustible gas, CO 2 , present in the atmosphere and formed during respiration, usually obtained from coal, coke, or natural gas by combustion, from carbohydrates by fermentation, by reaction of acid with limestone or other carbonates, or naturally from springs: used extensively in industry as dry ice, or carbon dioxide snow, in carbonated beverages, fire extinguishers, etc.

carbon dioxide British

noun

1. Also called: carbonic-acid gas. a colourless odourless incombustible gas present in the atmosphere and formed during respiration, the decomposition and combustion of organic compounds, and in the reaction of acids with carbonates: used in carbonated drinks, fire extinguishers, and as dry ice for refrigeration. Formula: CO 2

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 carbon dioxide Scientific

1. A colorless, odorless gas that is present in the atmosphere and is formed when any fuel containing carbon is burned. It is breathed out of an animal's lungs during respiration, is produced by the decay of organic matter, and is used by plants in photosynthesis. Carbon dioxide is also used in refrigeration, fire extinguishers, and carbonated drinks. Chemical formula: CO 2 .

carbon dioxide Cultural

1. A compound made up of molecules containing one carbon atom and two oxygen atoms.

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Carbon dioxide is normally found as a gas that is breathed out by animals and absorbed by green plants. The plants, in turn, return oxygen to the atmosphere. (See carbon cycle and respiration.)

Carbon dioxide is also given off in the burning of fossil fuels (see greenhouse effect).

Etymology

Origin of carbon dioxide

First recorded in 1870–75

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How does carbon-dioxide compare to similar and commonly confused words? Explore the most common comparisons:

• carbon monoxide vs. carbon dioxide

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Oxygen leaves the body as both water and carbon dioxide, while hydrogen exits only as water.

From Science Daily

"Though the Sun was very slightly dimmer, levels of atmospheric carbon dioxide were much higher."

From Science Daily

It predicts some 38.1 billion metric tons of fossil carbon dioxide emissions this year alone.

From Salon

Its atmosphere is extremely thin and composed mostly of carbon dioxide, which means far less electrical charge is needed to trigger sparks than on Earth.

From Science Daily

Ships emit about 3% of global carbon dioxide, according to the International Maritime Organization, the United Nations’ maritime regulator.

From The Wall Street Journal

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.