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 process is called carbonation, in which carbon dioxide from the air seeps into the concrete and reacts with calcium-rich compounds, leaving behind calcite, a hard crystalline mineral. — Sam MacDonald, Scientific American, 11 July 2026

This tab also tracks the number of meals donated to those in need, along with the amount of carbon dioxide emissions those donations prevented. — Chiara Kim, PEOPLE, 10 July 2026

When a Falcon 9 rocket takes off, its engines expel water vapor and carbon dioxide. — Chelsea Gohd, Space.com, 10 July 2026

The company emitted 20 million metric tons of carbon dioxide equivalent in 2025, up from 16 million metric tons the prior year, Microsoft said Thursday in its annual sustainability report. — Matt Day, Fortune, 9 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