Is it permissible to describe Fatimah (may Allah be pleased with her) as "our mother," or is this restricted to the wives of the Prophet (peace be upon him)?

The title "Mothers of the Believers" is exclusively for the wives of the Prophet, peace be upon him, with whom he contracted marriage and consummated it. This is based on the Almighty's saying: "The Prophet is more worthy of the believers than themselves, and his wives are their mothers." They are the Mothers of the Believers in terms of sanctity, respect, veneration, and the perpetual prohibition of marrying them. This title is not applied to others, such as the daughters of the Prophet, peace be upon him.