tholus

Etymology
From. .

Noun

 * 1)  A small domical mountain or hill.
 * Hecates Tholus is a Martian volcano.
 * 1) A round building, dome, or cupola.
 * 2)  Part of the apical structure of the asci of some lichen species.
 * 1)  Part of the apical structure of the asci of some lichen species.

Etymology
From.

Noun

 * 1) dome, cupola, rotunda