A vestibule, for one, is an entryway or small room that serves as a transition between the outside and the interior of a building. It is typically located at the entrance of a house or other structure and is often used to provide a buffer from the elements. Vestibules are also commonly used in public buildings such as schools, hospitals, and government offices. They can be used to separate different areas of a building, such as a lobby from a hallway, or to provide a secure area for visitors to wait before being admitted.