It is narrated from Sayyida Aisha Siddiqa (may Allah be pleased with her), she says: I took Abdullah bin Zubair (may Allah be pleased with him) 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: His name is Abdullah, and (Aisha!) you are Umm Abdullah.
Hadith Referenceالفتح الربانی / أبواب فى فضائل بعض الصحابة الكرام / 11783
Benefits: … This Abdullah ibn Zubair radi Allahu anhu was the nephew of Sayyidah Aisha radi Allahu anha, while Sayyidah Aisha radi Allahu anha herself had no children. Therefore, the Prophet sallallahu alayhi wa sallam gave her the kunyah (honorific title) after her nephew’s name.