cavum

Etymology
..

Noun

 * 1)  A recess or hollow.
 * 2) The lower part of the concha of the ear adjoining the origin of the helix.
 * 3) The nasal cavity.
 * 4)  A fallstreak hole.

Etymology 1
Substantive of.

Noun

 * 1) a hollow, hole, cavity, depression, pit, opening
 * 2) a cave, burrow, cavern