From Citizendium, the Citizens' Compendium
- Islam : Religion founded by Muhammad whose sacred book is the Qur'an (Koran).
- Religion : Belief in, and systems of, worshipful dedication to a superhuman power or belief in the ultimate nature of existence.
- Sunni : The main branch of Islam, which treats authority as following in the line of the first four "righteously guided" caliphs, as opposed to the Shi'ite dynastic line from the son-in-law of the Prophet
- Shi'a : A Muslim who believes that the line of religious authority derives from the Household of the Prophet Muhammad (Ahl ul-bayt), through the line of his son-in-law, Imam Ali