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

Idling of vehicles with engines that burn fossil fuels also emits climate-warming greenhouse gases like carbon dioxide, though climate concerns are not the primary target of anti-idling laws. — Richard Marcantonio, The Conversation, 31 July 2026

Under the European Union’s zero carbon dioxide emissions target for autos in 2035, the next big hurdle requires an EV market share of around 60% by 2030. — Neil Winton, Forbes.com, 29 July 2026

Once fully commissioned, it is expected to reduce carbon dioxide (CO2) emissions by nearly five million metric tons annually. — Georgina Jedikovska, Interesting Engineering, 27 July 2026

The acid made carbon dioxide already dissolved in the seawater more available for photosynthesis, and the microalgae grew about three times faster. — New Atlas, 27 July 2026

Word History

First Known Use

1867, in the meaning defined above

Rhymes for carbon dioxide

• acetamide
• acetonide
• acidified
• antimonide
• beatified
• benzaldehyde
• borohydride
• chalcogenide
• commodified
• decalcified
• declassified
• disaccharide

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