The Difference Between a Mosque and a Prayer Hall, and the Greeting of the Mosque

Question:
Honorable Shaykh, may Allah grant you success. This questioner says: What is the difference between a mosque and a prayer hall? And is it obligatory to pray the greeting of the mosque when entering a prayer hall?

Answer:
A mosque is an enclosed area that has doors and walls. As for a prayer hall, it is like that, and a mosque is also an endowment. As for a prayer hall, it is found in offices and government departments. This is a prayer hall and does not take on the rulings of a mosque. It is permissible for a menstruating woman to sit in it, and it is permissible, because it is not a mosque. The mosque is what has a wall and doors and is also an endowment. Yes.