aditus
/ˈadɪtəs/noun
Anatomy and Zoology. The opening of or entrance into a cavity or channel (frequently with distinguishing scientific Latin word or phrase denoting the cavity or channel); especially (more fully aditus ad antrum) the opening between the tympanic cavity and the mastoid antrum.
Origin
Mid 19th century; earliest use found in Robley Dunglison (1798–1869), physician and medical writer. From classical Latin aditus, lit. ‘approach’.