vestibule

noun

• 1an antechamber, hall, or lobby next to the outer door of a building.
• an enclosed entrance compartment in a railway carriage.

• 2 Anatomy a chamber or channel opening into another, in particular:
• the central cavity of the labyrinth of the inner ear.
• the part of the mouth outside the teeth.
• the space in the vulva into which both the urethra and vagina open.