Asad ibn Hāshim (Arabic: أسد بن هاشم) was the son of Hashim ibn Abd Manaf and the brother of Abd al-Muttalib. He was the father of Fatima bint Asad, the mother of Ali and the cousin and wife of Abu Talib. Asad was a very respected person among the Hashimi Arab tribe. He was a merchant and very often helped the poor. His name means Lion (a brave one). His descendants usually use the surnames Al-Hashimi, Al-Asadi, Sayyid, or Sharif, while some of his descendants avoid using any surname.
Sayyid is an honorific title of Hasanid and Husaynid lineage, recognized as descendants of the Islamic prophet Muhammad through his daughter Fatima and Ali's sons Hasan and Husayn. The title may also refer to the descendants of the family of the Bani Hashim through the Prophet's great-grandfather Hashim, and others including Hamza, Abbas, Abu Talib, and Asad ibn Hashim.
See also Sharif, which has a good description of three types of identification for that term and co-relates to this term. In its narrowest sense, a sayyid is a descendant of Husayn ibn Ali, but the term is also more generally used for descendants of The Prophet.