vestibule

Short definition from Wiktionary

Noun

1. 1
   A small entrance hall, antechamber, passage, or room between the outer door and the main hall, lobby, or interior of a building.
2. 2
   A small entrance hall, antechamber, passage, or room between the outer door and the main hall, lobby, or interior of a building: A large entrance hall in a temple or palace.
3. 3
   A small entrance hall, antechamber, passage, or room between the outer door and the main hall, lobby, or interior of a building: An enclosed entrance at the end of a railway passenger car.
4. 4
   Any of a number of body cavities or channels, serving as or resembling an entrance to another bodily space.
5. 5
   Any of a number of body cavities or channels, serving as or resembling an entrance to another bodily space: The central cavity of the bony labyrinth of the inner ear or the parts (such as the saccule and utricle) of the membranous labyrinth that it contains.
6. 6
   Any of a number of body cavities or channels, serving as or resembling an entrance to another bodily space: The part of the left ventricle below the aortic orifice.
7. 7
   Any of a number of body cavities or channels, serving as or resembling an entrance to another bodily space: The part of the mouth outside the teeth and gums.
8. 8
   Any of a number of body cavities or channels, serving as or resembling an entrance to another bodily space: Clipping of vulval vestibule: the space in the vulva between the labia minora and into which both the urethra and vagina open.

Verb

1. 1
   To furnish with a vestibule or vestibules.