Origin: Greek prefix mono-
Monoxide has 2 different meanings across 1 category:
an oxide containing just one atom of oxygen in the molecule
"The chemical formula for carbon monoxide reveals that it is a simple oxide containing exactly one atom of oxygen bonded to a single carbon."
any oxide containing a single oxygen atom in each molecule or formula unit
"The chemical analysis confirmed that carbon monoxide is an unstable gas where every molecule contains exactly one oxygen atom bonded to a carbon atom."