Carbonic acid gas and Dioxide

Carbonic acid gas noun - A heavy odorless colorless gas formed during respiration and by the decomposition of organic substances; absorbed from the air by plants in photosynthesis.

Dioxide and carbonic acid gas are semantically related. In some cases you can use "Dioxide" instead a noun phrase "Carbonic acid gas".

Dioxide noun - An oxide containing two atoms of oxygen in the molecule.

Carbonic acid gas and dioxide are semantically related. Sometimes you can replace phrase "Carbonic acid gas" with "Dioxide", this terms are similar.