Dioxide \Di*ox"ide\ (?; 104), n. [Pref. di- + oxide.]

(Chem.)
   (a) An oxide containing two atoms of oxygen in each molecule; binoxide.
   (b) An oxide containing but one atom or equivalent of oxygen to two of a metal; a suboxide. [Obs.]

Carbon dioxide. See Carbonic acid, under Carbonic.

Source: Webster's Revised Unabridged Dictionary (1913)