A myth is not only a legendary or traditional story, usually one concerning a superhuman being and dealing with events that have no natural explanation (See mysterious), but also an unproved belief and an invented idea or story: "The story of Atlas holding up the world on his shoulders is a myth." "It is a myth that all sharks are dangerous." "His excuses for his failure are only myths." A fable is a simple story with animals as characters, one designed to teach a moral truth: "His favorite fable was the one about the fox and the grapes." Fable is also applied to stories about supernatural beings (resembling a myth), to accounts of extraordinary events, and to outright falsehoods: "Jim's account of flying with self-made wings is an outright fable." A legend is a tradition or story handed down from earlier times and now popularly accepted as true, believable, or delightful: "A legend forms the basis of Irving's short story about a headless horseman in 'The Legend of Sleepy Hollow. ' "
Dictionary of problem words and expressions. Harry Shaw. 1975.