1. (noun)monoamine oxidase, MAO an enzyme that catalyzes the oxidation of many body compounds (e.g., epinephrine and norepinephrine and serotonin) Synonyms: monoamine oxidase
2. (noun)Mao, Mao Zedong, Mao Tsetung Chinese communist leader (1893-1976) Synonyms: monoamineoxidase