(chemistry) any oxide containing a single oxygen atom in each molecule or formula unit

plural of monoxide

(inorganic chemistry) A colourless, odourless, flammable, highly toxic gas

(informal) dihydrogen monoxide (water (H₂O), but not hydrogen peroxide (H₂O₂) or the hydroxyl radical (-OH))

(inorganic chemistry, usually humorous) H₂O, water.

(inorganic chemistry) nitrous oxide

Nitric oxide.

Alternative spelling of sulfur monoxide

(inorganic chemistry) An unstable binary compound, SO, of sulfur and oxygen.

(inorganic chemistry) The oxide of lead, PbO, that occurs as the minerals litharge and massicot