What is a myth or a legend?

Answer 1

They're essentially synonymous. They refer to folklore stories, generally untrue, though those who tell them may believe them to be true and in some cases they may be loosely related to actual historical events.

Answer 2

Legends or myths are usually created by ancient philosophers to explain the origin of something or the reason something happens. For example, some philosophers believed that eclipses signal the unhappiness of a god.