Shisei Seido (the system of clans and hereditary titles) is a system made in ancient Japan in which the Imperial Court gave the nobles living in the capital and the powerful local clans a clan name and a hereditary title according to each person's degree of contribution to the state (Yamato Sovereignty) and the position the person occupies in the Government of the Imperial Court and let them kept the special privilege by the hereditary system.
氏姓制度（しせいせいど）とは、古代日本において、中央貴族、ついで地方豪族が、国家（ヤマト王権）に対する貢献度、朝廷政治上に占める地位に応じて、朝廷よりウヂの名とカバネの名とを授与され、その特権的地位を世襲した制度。