vestibule
From ZooTerms (Dictionary of Invertebrate Zoology)
vestibule also vestibulum (noun; plural vestibula; Latin vestibulum, entrance hall): 1. A cavity forming an entryway to another cavity or passageway.
2. (Annelida) Containing a penis or male porophore and pore fissure.
3. (Arthropoda: Crustacea) In Ostracoda, a space between the duplicature and outer lamella.
4. (Bryozoa) The area through which the lophophore passes.
5. (Rotifera;Chaetognatha) An opening leading to the mouth.
6. (NEMATA) see stoma, cheilostome.
