Sunni
sunniyy (Arabic)
Main group in Islam, making up 90% of the religion's adherents. Has been dominating almost continuously since 661, when the Shi'is departed from the main fold (the Kharijis left in 658). Sunni Islam claims to be the continuation of the Islam as it was defined through the revelations given to Muhammad and his life, a claim which is substantiated through the fact that Shi'i Islam for a number of decades had very little following and had no real, formal organisation. As for the theology, Sunni Islam represents no more of a continuation of Islam than the other orientations.
Sunni Islam has its name from its identification with the importance of the Sunna (the examples from the hadiths), which earlier than in Shi'i Islam was established as central to the true image of Islam. This was connected to the need of establishing a law, called Shari'a (for which the hadiths served as a central source), as Sunni Islam was the religious orientation of the rulers, while the Shi'is did not establish administrative organisations for yet a long time to come.
The actual theological and ritual differences between Sunni and Shi'i Islam, came over a couple of centuries with development. For a long time, Sunni Islam was defined from Shi'i Islam by its adherence to the Caliph as the leader of the Muslim world.
There are many smaller and some larger differences between Sunni and the two other orientations, in all aspects of the religion. Sunni and Shi'i Islam share only three core doctrines, oneness of God, the belief in the revelations of Muhammad, and the belief in resurrection on the Day of Judgment.
Sunni Islam has a different set of hadiths from Shi'i Islam. In Sunni Islam, there are performed 5 prayers a day, while Shi'i Islam has only 3. Sunni Islam puts far more importance into the hajj to Mecca, while Shi'i Islam has some other central pilgrimages as well. Sunni Islam revere Ali, but does not hold him up the only true continuation of the tradition from Muhammad, and has no emphasis on him bringing on a divine light from the Prophet.