Musnad Ahmad 1153:2223

Yunus narrated to us, he said: Hammad—meaning Ibn Zayd—narrated to us, from Hisham ibn Urwah, from his father, from Aisha, that she said: "O Messenger of Allah, all of my companions have a kunya (patronymic) except for me." He said: "Take a kunya by your son, Abdullah ibn al-Zubayr." So she was called Umm Abdullah until she died.