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

That didn’t bother the three roaches crawling on the floor by a carbon dioxide tank inside the storage room behind the office. —David J. Neal, Miami Herald, 13 Mar. 2026

The current proposal would remove 118 million emission allowances from the total pool of allowances governed by the state with each allowance equal to a permit to emit one metric ton of greenhouse gases in carbon dioxide equivalent. —Chaewon Chung march 9, Sacbee.com, 9 Mar. 2026

This means that those carbon dioxide bubbles begin to form the minute the baking powder is mixed into your batter. —Katie Rosenhouse, Southern Living, 9 Mar. 2026

The levels of carbon dioxide, methane and nitrous oxide in the atmosphere all increased in 2025. —Michael Wysession, Fortune, 6 Mar. 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