Vestibule can have the following meanings:

• A large entrance, reception area, antechamber, or room
• A small room or passage that connects the outer door of a building to the interior of the building
• An area in a train where people get on and off. If there are seats at all, they are often less comfortable folding ones.
• A body cavity leading to another cavity; often used of the inner ear.
• The popular IGN Vestibule message board.