A Sharif is a traditional Arab tribal title given to those to serve as the protector of the tribe and all tribal assets, property, land, wells etc.
It is used, in the Muslim tradition, to refer to those claiming descent from the Prophet Muhammad through Hasan, son of his daughter Fatima Zahra and son-in-law Ali ibn Abi Talib. (Descendents of another son, Husain, are often referred to as Sayyid.) From 1201, this family held the office of the Sharif of Mecca and descendants now rule Jordan.
The English term sheriff is unrelated.
See also
