tholos

noun, plural tho·loi [thoh-loi] /ˈθoʊ lɔɪ/.

1. (in classical architecture)
   1. a circular building.
   2. a small, round structure, as a lantern.
   3. a circular subterranean tomb, lined with masonry.
2. a subterranean domed tomb chamber of the Mycenaean age.

noun plural -loi (-lɔɪ)

1. a dry-stone beehive-shaped tomb associated with the Mycenaean culture of Greece in the 16th to the 12th century bc