myth

noun

• 1a traditional story, especially one concerning the early history of a people or explaining a natural or social phenomenon, and typically involving supernatural beings or events:ancient Celtic myths [mass noun]:the heroes of Greek myth

• 2a widely held but false belief or idea:the belief that evening primrose oil helps to cure eczema is a myth, according to dermatologists
• a fictitious or imaginary person or thing: nobody had ever heard of Simon’s mysterious friend—Anna said he was a myth
• an exaggerated or idealized conception of a person or thing:the book is a scholarly study of the Churchill myth