carbon dioxide vs dioxide

carbon dioxide and dioxide both are nouns.

Word	Noun	Adjective	Verb	Adverb
carbon dioxide	Yes	No	No	No
dioxide	Yes	No	No	No

As nouns, dioxide is a hypernym of carbon dioxide; that is, dioxide is a word with a broader meaning than carbon dioxide:

carbon dioxide: a heavy odorless colorless gas formed during respiration and by the decomposition of organic substances; absorbed from the air by plants in photosynthesis
dioxide: an oxide containing two atoms of oxygen in the molecule

Other hypernyms of carbon dioxide include greenhouse emission, greenhouse gas.

carbon dioxide (noun)	dioxide (noun)
a heavy odorless colorless gas formed during respiration and by the decomposition of organic substances; absorbed from the air by plants in photosynthesis	an oxide containing two atoms of oxygen in the molecule