It is narrated from Sayyida Aisha (may Allah be pleased with her), she says: I brought (my nephew) Ibn Zubair to the service of the Noble Prophet (peace and blessings be upon him). The Prophet (peace and blessings be upon him) gave him a chewed date and said: This is Abdullah and you are Umm Abdullah.
Hadith Referenceالفتح الربانی / كتاب الخلافة والإمارة / 12441
Benefits: … Sayyidah Aisha radi Allahu anha was the maternal aunt (khala) of this child, and the maternal aunt is like the mother herself. Therefore, the Prophet sallallahu alayhi wa sallam gave Sayyidah the kunyah (honorific title) of Umm Abdullah.