'Monoxide' definitions:

Definition of 'monoxide'

From: WordNet
noun
An oxide containing just one atom of oxygen in the molecule

Definition of 'Monoxide'

From: GCIDE
  • Monoxide \Mo*nox"ide\, n. [Mon- + oxide.] (Chem.) An oxide containing one atom of oxygen in each molecule; as, barium monoxide. [1913 Webster]