Sunan Ibn Majah, Volume 5, Book 33, Hadith 3739 (DarusSalam) ⓘ
It was narrated from Aisha that she said to the Prophet: "All of your wives have a Kunyah except me." He said: "You are Umm Abdullah".
حَدَّثَنَا أَبُو بَكْرٍ، حَدَّثَنَا وَكِيعٌ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ مَوْلًى، لِلزُّبَيْرِ عَنْ عَائِشَةَ، . أَنَّهَا قَالَتْ لِلنَّبِيِّ ـ صلى الله عليه وسلم ـ كُلُّ أَزْوَاجِكَ كَنَّيْتَهُ غَيْرِي . قَالَ " فَأَنْتِ أُمُّ عَبْدِ اللَّهِ " .
also referenced under: Hadith 3739 (Reference) & Book 33, Hadith 84 (In-Book)