[…] Someone wrote to Hazrat Amirul Momineen, Khalifatul Masih Vaa [in Urdu] that the Holy Prophetsa had asked Hazrat Fatimara about Hazrat Alira ‘Where is the son of your chacha [paternal uncle]?’ Similarly, the Holy Prophetsa had used the word chacha for Hazrat Abbasra and Hazrat Abu Talib. Moreover, Hazrat Alira had used the word chachi [wife of the paternal uncle] for Hazrat Khadijara. The person then requested Huzooraa for an explanation for the usage of this word. Huzoor-e-Anwaraa, in his letter dated 13 December 2020, gave the following reply to this question:
“Every society has some customs and idioms for everyday use, which can only be understood by keeping the context of that society before us. Hence, in some families, according to the family’s customs or idioms, the father’s relationship with a person is also used to refer to the children. Since Hazrat Alira was the son of the Holy Prophet’ssa paternal uncle, according to the prevalent social custom, the Holy Prophetsa asked his daughter, ‘Where is your uncle’s son?’
Moreover, in Arabia, it was a common practice to use the phrase
يَا ابْنَ أَخِيّ or يَا ابْنَ عَمِّ
i.e. ‘O the son of my uncle’ or ‘O the son of my brother’ etc. and this practice exists to this day. Hence, an older person may use the phrase
يَا ابْنَ اخِي
meaning ‘O the son of my brother’ to address a younger person and similarly a wife may use the words
يَا ابْنَ عَمِّ
meaning ‘O the son of my uncle’ instead of calling her husband by his name.
As far as Hazrat Ali’sra use of the word chachi [paternal uncle’s wife] for Hazrat Khadijara is concerned, in Arabic the word ‘amati is used for both phuphi [paternal aunt] and chachi [paternal uncle’s wife]. It seems that you may have read the word ‘amati somewhere and translated it [into Urdu] as chachi whereas the translation of this word would be phuphi with reference to Hazrat Khadijara and Hazrat Alira because Hazrat Khadijara and Hazrat Abu Talibra share a common patrilineal ancestor in Qusay bin Kilab in the fifth generation before them. Therefore, Hazrat Khadijara is the paternal aunt of Hazrat Alira in terms of the relationship.”