Definition of "vestibular"

vestibular

/vɛˈstɪb.jʊl.ə/

adjective
not comparable
1. Of or pertaining to a vestibule in a building (or railway coach).
  Quotations
  […] while the outer world was fenced off by the interposed atrium or vestibular cloister, […] .
  1861, Alexander James Beresford Beresford Hope, The English Cathedral of the Nineteenth Century‎, page 158
  Originally, it was intended that the stock should be vestibular throughout, but when the drawings were submitted to the Prince of Wales, he cut out this feature, saying that a railway journey afforded one of the very few occasions when he was able to enjoy absolute privacy—a feature which the vestibule would tend to abolish.
  1950 August, “Notes and News: Royal Train at Croydon”, in Railway Magazine, pages 569-570
2. (anatomy) Of, pertaining to, or functioning as a vestibule (body cavity).
3. (anatomy) Of or pertaining to the vestibule of the inner ear and the perception of body position, balance and movement.
  Quotations
  Ampulla of the perpendicular semicircular canal, receiving a fasciculus from the superior branch of the vestibular nerve […] .
  1859, William James Erasmus Wilson, William H. Gobrecht, A System of Human Anatomy, General and Special
4. (dentistry) Of or pertaining to the surface of a tooth that is directed outward toward the vestibule of the mouth, including the buccal and labial surfaces, and opposite the lingual (or oral) surface.
noun
plural vestibulars
1. (education) A competitive examination used by Brazilian universities to select students.
  Quotations
  Students usually complete high school when they are seventeen years old. If they want to go to college or university, they must pass a difficult test called the vestibular, which takes two or three days to write.
  2002, Malika Hollander, Brazil: The People, page 23