noun \ˈves-tə-ˌbyül\

Definition of VESTIBULE

: any of various bodily cavities especially when serving as or resembling an entrance to some other cavity or space: as a (1) : the central cavity of the bony labyrinth of the ear (2) : the parts of the membranous labyrinth comprising the utricle and the saccule and contained in the cavity of the bony labyrinth b : the space between the labia minora containing the orifice of the urethra c : the part of the left ventricle of the heart immediately below the aortic orifice d : the part of the mouth cavity outside the teeth and gums

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