This is the 3705th most frequent Japanese word.
お母さん
Mother.
The term 'お母さん' in this context addresses someone's mother directly with respect. It shows care and interest in the well-being of the addressee's mother.
お母さんは元気ですか?
Is your mother well?
In this sentence, 'お母さん' is used to refer specifically to the speaker's own mother in a respectful and polite fashion. It is often used in personal interactions to show endearment and closeness.
私はお母さんに手紙を書きました。
I wrote a letter to my mother.
Here, 'お母さん' is used to refer to someone else's mother respectfully. Adding the pronoun '彼の' (his) specifies whose mother is being discussed.