<p><strong>Noun</strong></p><ul><li>plural flies. Also called true fly.</li><li>any of numerous two-winged insects of the order Diptera, especially of the family Muscidae, as the common housefly.</li><li>any of various winged insects, as the mayfly or firefly.</li><li>Angling. a fishhook dressed with hair, feathers, silk, tinsel, etc., so as to resemble an insect or small fish, for use as a lure or bait.</li><li>Fly, Astronomy. the constellation Musca.</li></ul>