Myth comes from the Greek mythos, which means an event (or story). A term sometimes used in a very broad sense (actually in agreement with its original meaning in Greek) to denote a story; more often the word is used in a narrower sense (for example, an event or a collection of events (plots) through which a culture or religion defines itself).
Claude Lévi-Strauss, Roland Barthes and Paul Ricœur, each in his own way, discussed the subject of the myth.