What's the difference between a pagan and a heretic? Between an atheist and an agnostic? You've heard these words before ... but do you know what they mean? Here's a refresher course.

Heathen: A believer in a religion other than Judaism, Christianity, or Islam.

Pagan: The same thing as a heathen.

Lapsed Catholic: Originally used to describe someone who had left Catholicism and returned to paganism.

Old Catholic: A member of a sect of Catholicism that refuses to believe the pope is infallible.

Spiritist: A person who believes in the ability to communicate with the dead via seances, ouija boards, table tapping, and so forth.

Deist: A person who believes in God, but who believes he (or she or it) did not reveal a particular religion for people to worship.

Pantheist: Someone who believes that all things are part of God.

Agnostic: Someone who believes that there's no proof that God exists but who accepts the possibility that there might be a God.

Atheist: A person who is sure that God does not exist.

Blasphemer: Someone who speaks irreverently to God or about God.

Heretic: A Catholic who rejects some tenets of the Catholic faith, but not all of them.

Schismatic: Someone who accepts all tenets of the Catholic faith, but refuses to acknowledge the authority of the pope.

Apostate: Someone who left the religion they were born into to join another faith.

Infidel: A person who rejects Christianity (for Muslims it means someone who rejects Islam).