[alikhan0]

The precise word is used in the same verse that you have quoted. The context of this is the following: The angels of Allah had brought Ibrahim and Ibrahim's wife the good news of a son named Ishaq and a grandson, Yaq'ub . There were two people in the room. The term 'Ahlul Bayt' is a plural; therefore, Ibrahim and his wife were included in the categorization of Ahlul Bayt. You can check this in the available online version of Tafsir ibn Kathir, though I would refrain from relying on it exclusively.

Ultimately, the term 'Ahlul Bayt' refers to family; all the family. This includes wives. The Shi'a exclude wives from the definition, but their sources for doing so are highly dubious.

I pray that you enter Islam and walk in the sight of Allah purified, and I hope that this has helped.