A two-winged insect belonging to a large group called the Diptera. The mouthparts of flies are adapted for sucking and sometimes also for piercing and biting. Fly larvae (maggots) may infest human tissues and cause disease.
An insect belonging to the order Diptera, characterized by sucking mouth parts, one pair of wings, and complete metamorphosis, such as the housefly, horsefly, or deerfly. The term is sometimes applied to insects belonging to other orders.