1) Opening 2) Orifice 3) Porta 
An introitus is an entrance that goes into a canal or hollow organ. The vaginal orifice is an introitus. ...
The vaginal opening. ... (27 Sep 1997) ... 
(in-tro´ĭ-tәs) Latin word meaning an entrance; a term used in anatomy.
An aperture.
Type: Term Pronunciation: in-trō′i-tŭs Definitions: 1. The entrance into a canal or hollow organ, as the vagina.
Introitus: In anatomy, an introitus is an entrance, one that goes into a canal or hollow organ. The introitus of the facial canal is the entrance to the facial canal, a passage in the temporal bone of the skull through which the facial nerve (the 7th cranial nerve) travels. The introitus of the vagina is the opening to the vagina: The Latin word 'i...
Introitus is Latin for entrance
[n] - entrance or opening to a hollow organ or tube (especially the vaginal opening)
noun entrance or opening to a hollow organ or tube (especially the vaginal opening); `the introitus of the vagina`
Latin intro = within, and ire = to go, hence, an orifice or point of entry to a cavity or space.