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

China's carbon dioxide emissions from its power sector fell by almost 3% during the first half of this year as its growth in solar power matched the rise in electricity demand. —Dinah Voyles Pulver, USA Today, 24 Sep. 2025

This process sucked carbon dioxide out of the atmosphere. —Chris Impey, The Conversation, 23 Sep. 2025

In children, mucus can become trapped in the bronchioles—some of the tiniest airways in the lungs—and prevent the lungs from exchanging oxygen and carbon dioxide, says James Campbell, vice chair of the committee on infectious diseases at the American Academy of Pediatrics. —Liz Szabo, Scientific American, 23 Sep. 2025

When burned, its carbon combines with oxygen, which creates carbon dioxide (CO2). —Daniel Manzo, ABC News, 23 Sep. 2025

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