三朝元老　

◎ 三朝元老 sān cháo yuánlǎo

(1) [a veteran statesman who have served three emperors in a row]∶原指先后受三世皇帝重用的大官;后用来讽刺在几个王朝当官的人

(2) [the most senior employee in a government organization]∶在某个政府部门任职很久,已经经历了几个领导的人,也比喻在一个部门工作时间长、资格老的人