An old man, especially, one who has authority and respect; an elder, a chief; a title given to various Mohammadan saints; the head of an Arab tribe; the term also used to designate the descendants of Mohammad, of Abubakr, and Omar. [Wilson’s Glossary]

The designation of those Musalmans who profess to be descended from the first or second caliphs or from the prophet’s uncle Abbas. [P Ramanatha Aiyer’s The Law Lexicon]