The full term is (pardon me, but my spelling of Arabic words in English is very very horrible) "shi'at ali" or "partisans of Ali", a relative of Muhammad, who was a favored heir to the position of Caliph after Abu Bakr, the first caliph died. However, he was passed in favor of someone else and when finally given the position, I believe he was assasinated. Then, his supporters clashed with those who supported the other candidate and so the Sunni (orthodox) and Shi'ite (pronounced "shee-ah" whenever I've heard a muslim say it, these were the supporters of Ali) sects or groups were formed. Don't quote me on this as my memory of World History class and discussions with a friend of mine who is part of a Shia (I prefer this spelling) sub-sect isn't the best.