answer:It’s actually a case convergent evolution. The noun comes from the Middle High German word “Flügel,” which means “wing.” It entered Old English as the word “flȳge” or “flēoge,” which referred to any winged insect. The verb comes from the Proto-Germanic word “fleugana,” which means “to fly.” It entered Old English as the word “flēogan,” which also means “to fly.” Simplifications in spelling and pronunciation over time led both words to become “fly.” Technically, there is no insect that is just called a “fly.” What most people call “flies” are actually supposed to be called “house flies.” But they are so common that the first word gets dropped. It’s only an important distinction in biology, where the word “fly” (in noun form) most properly refers to insects of the order Diptera (the so-called “true flies,” which are distinguished by their use of a single pair of wings for flying).