A vestibule (Latin: vestibulum) is a large, extensive space or set of rooms in a building or house and, in particular, in a theatre, opera, concert hall, trade fair, cinema, etc., adjacent to the auditorium. It is a rest area for the public (spectators) and a place used especially before the "Performance (show)" performance and during breaks, but also as a place for celebrations after the performance. Sometimes (as in the case of large opera houses) the French voice foyer is used.

A lobby is generally a wide, purpose-built hallway surrounding the main entrance hall of a building (office, hotel, etc.) or, less commonly, a home.

In a hotel, the lobby is a large entrance room that connects the outside with the reception "Reception (hospitality)") and other rooms and services: cafeteria, restaurant, elevators, lounges and others.

A foyer in a house is generally a small area or room adjacent to the front door through which the rest of the rooms are accessed.

The Greeks did not use atriums but they did use vestibules and called them pronaos or prothyron (rather, colonnaded porch). The name vestibule was taken because a sacred fire was kept in it in honor of Vesta "Vesta (mythology)") similar to the one kept by the Vestals. They were common in ancient Greek temples. Due to the construction techniques available at the time, it was not possible to build large spans. Consequently, many entrances had two rows of "Column (architecture)") columns (distyle) that supported the roof and created a distinct space at the entrance.

In Roman houses or domus, the vestibule was a space between the interior of a building and the street. It was quite wide, and you had to pass through it before entering the atrium and there those who were going to the house would wait for the door to open. To close the vestibule there would probably be nothing more than gates "Gate (gate)") or iron railings in the middle intercolumniation and podium "Podium (architecture)") in the other intercolumniations.

In the houses of the powerful, the lobby had to be very spacious because of the multitude of clients and flatterers who came to greet and say good morning at prime time, as can be seen from what Marco Valerio Marcial says. At one end of the hall the doorman, who was called famulum atriensem, had his room.[1]​.