tholos
A dome, or domed building; a cupola.
On the way they pointed out the tennis court and the old summerhouse, a mock tholos, Doric by way of Pompeii, and Stanford White, and (said Francis, who was scornful of this Victorian effort at classicism) D. W. Griffith and Cecil B. De Mille.
A dome-shaped tomb from the Mycenaean period of Ancient Greece.
Where it comes from
From Ancient Greek θόλος (thólos, “dome”). Doublet of tholus and thole.
Adapted from the Wiktionary entry tholos (CC BY-SA 4.0).