摄政

Classic example: 周公 — the Duke of Zhou governed for the young King Cheng 成王 after King Wu's death, and is held up in Confucian tradition as the model regent who returned power voluntarily. 摄政王 means 'prince regent' (e.g. 多尔衮, Dorgon, for the young Shunzhi Emperor).

memory

摄 means 'to take/manage on someone else's behalf' (also seen in 摄影 'photography' — literally 'capturing image'). 政 = government. So 摄政 = 'managing the government for another'.