- mosquitoA small flying insect of the family Culicidae, the females of which bite humans and animals and suck blood, leaving an itching bump on the skin, and sometimes carrying diseases like malaria, dengue and yellow fever.
- musketA kind of firearm formerly carried by the infantry of an army, originally fired by means of a match, or matchlock, for which several mechanical appliances (including the flintlock, and finally the percussion lock) were successively substituted; ultimately superseded by the rifle.
- muscaAn autumn constellation of the southern sky, said to resemble a fly, between the constellations of Carina and Apus.
- muscarineAn extremely poisonous alkaloid, obtained from fly agaric, that disrupts the action of acetylcholine neurotransmitter.
- muschetorA black spot like an ermine spot, but without its three specks.
- muscicideAny substance that kills flies.
- muscifugeSomething which repels or kills flies, typically a plant; a fly repellent. Also spelled "muscafuge" (1844) by Henry Stephens, who claimed to have coined it.
- muscoidAny fly in the superfamily Muscoidea.