摄政

Classic example: 周公摄政 — the Duke of Zhou (Zhōugōng) 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 (shèzhèngwáng) 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]'.