Entry 1 sense Webster, 1913 Vestibular /vĕsˌ-tĭb'-yo͞ol-ẽr/ · Ves·tib·u·lar · IPA /vɛˈstɪb.jəl.ɚ/ 01 a. Of or pertaining to a vestibule; like a vestibule. 1. Of or pertaining to a vestibule; like a vestibule.