1. mao(n = noun.substance) monoamine oxidase - an enzyme that catalyzes the oxidation of many body compounds (e.g., epinephrine and norepinephrine and serotonin);
is a kind of enzyme
2. mao(n = noun.person) mao tsetung, mao zedong - Chinese communist leader (1893-1976);
is a kind of commie, communist, revolutionary, revolutionist, subversive, subverter
See Mao Tsetung. [PJC]