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

Recent Canadian Wildfire smoke spread across a third of the United States but the bigger impact is that these fires have released roughly three times the amount of carbon dioxide as Canada’s total annual fossil fuel greenhouse emissions. — Jay Reddick, The Orlando Sentinel, 14 Aug. 2026

Just before rapid warming began, the forest canopies reached their greatest density in hundreds of thousands of years, likely reflecting favorable growing conditions as atmospheric carbon dioxide began to increase. — Regan E. Dunn, The Conversation, 13 Aug. 2026

Often, a swimmer takes a deep breath and hyperventilates before going under the water, causing a decrease of carbon dioxide in their body. — Chip Alexander, Charlotte Observer, 12 Aug. 2026

The reason is Venus’ extraordinarily thick atmosphere, composed mostly of carbon dioxide. — Kaif Shaikh, Interesting Engineering, 11 Aug. 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