Actually we already had a definition of myth: relating to, based on, or appearing in myths, which was my point: a traditional story, especially one concerning the early history of a people or explaining some natural or social phenomenon, and typically involving supernatural beings or events.
synonyms: folk tale, folk story, legend, tale, story, fable, saga, mythos, lore, folklore, mythology More
traditional stories or legends collectively.
"the heroes of Greek myth"
2.
a widely held but false belief or idea.