Why is it called Mrs. Guoguo?

Mrs. Guo Guo was the third sister of Yang Yuhuan, the favorite concubine of Li Longji, Emperor Xuanzong of the Tang Dynasty. She was a native of Yongle, Puzhou (now Ruicheng County, Shanxi) in the Tang Dynasty.

In his early years, he lived in Shu with his father, and he was also talented and beautiful. When she grew up, she married Pei, who died early. After Yang Guifei became favored by Tang Xuanzong, she missed her sister and asked Tang Xuanzong to welcome Mrs. Guo Guo and Yang Guifei's other two sisters to the capital together. Emperor Xuanzong of the Tang Dynasty called Concubine Yang's three sisters his aunts and gave them residences. In the early years of Tianbao, they were granted the titles of Lady Guo, Lady Han and Lady Qin.

Extended information:

Among the three ladies, Xuanzong doted on Mrs. Guo the most and gave her the privilege of visiting the palace at any time. However, Mrs. Guo Guo could not escape the fate of her beauty. During the Anshi Rebellion, she was shocked to hear the news of Yang Guozhong's death. She fled with Guozhong's wife Pei Rou. Officers and soldiers chased her. Seeing that there was nowhere to escape, she responded to Pei Rou's plea and stabbed Yang Guozhong's two children and Pei Rou to death with her own hands, and then waved Kill yourself with the sword.

Baidu Encyclopedia-Mrs. Guo Guo