I have encountered many people, predominantly atheists that throw around the names such as Isis, Horus and Osiris as examples of mythological characters that incorrectly are addressed as proponents of how the Christian faith came to be. In response to those very ridiculous and empty arguments I believe we should actually read the definition of “Myth”.
*The term myth is most often associated with fable or with the historically inauthentic (fiction) rather than with truth and objective reality. Hence some people apply myth to any part of the Christian message that includes the supernatural or miraculous (see Bultmann; demythologizing). Myth can also be used to describe the true but transcendent or ineffable quality of God’s revelation. This is beyond rational, linguistic description (see Brunner). Myth also connotes the language or imagery borrowed from the cosmological/cosmogonical (creation) myths to speak of God.
*Stanley J. Grenz, David Guretzki & Cherith Fee Nordling, Pocket Dictionary of Theological Terms (Downers Grove, IL: InterVarsity Press, 1999), p. 81-82