This is the 6387th most frequent Arabic word.
ابنها
Her son.
The word 'ابنها' indicates possession, meaning 'her son', with 'ها' referring to the third-person feminine singular.
هذا ابنها الذي يذهب إلى المدرسة كل يوم.
This is her son who goes to school every day.
The word 'ابنها' is used here as an object of the sentence, and it still conveys possession by a female person.
هل تعرف أي صف يدرس ابنها فيه؟
Do you know which class her son is in?
In this sentence, 'ابنها' describes whom the subject met, incorporating the notion of possession as 'her son'.