Carboxide \Car*box"ide\, n. [Carbon + oxide.]

(Chem.) A compound of carbon and oxygen, as carbonyl, with some element or radical; as, potassium carboxide.

Potassium carboxide, a grayish explosive crystalline compound, C6O6K, obtained by passing carbon monoxide over heated potassium.

Source: Webster's Revised Unabridged Dictionary (1913)