Analysis of information sources in references of the Wikipedia article "Princess Gyeguk" in English language version.
忠宣王妃薊國公主寶塔實憐 (Botashirin)
Buddhaśrī (Jiguo Imperial Princess)
An emperor's [...] sister or a favorite daughter was called a grand princess (zhang gongzhu); and his aunt or grand-aunt was called a princess supreme (dazhang gongzhu).
The emperor's agnatic aunt shall be called Princess Supreme [dazhang gongzhu]. The emperor's sisters shall be called Grand Princesses [zhang gongzhu].