What is the hall in Harry Potter called?

There are many halls in the Harry Potter universe, but I think you're asking about the Great Hall, the main dining hall of Hogwarts School of Witchcraft and Wizardry.

It's a grand, impressive hall with four long tables for each house (Gryffindor, Slytherin, Hufflepuff, and Ravenclaw), a high ceiling, and enchanted windows that change according to the weather outside.

Let me know if you had a specific hall in mind!