Umbra is a simple computer role-playing game, written in Python. The world is randomly-generated for new play every time, but there is an eventual goal and storyline. It was heavily influenced by rogue-like games, Alternate Reality, console RPGs, and the works of H.P. Lovecraft and Clark Ashton Smith.
The conical shadow projected from a planet or satellite, on the side opposite to the sun, within which a spectator could see no portion of the sun's disk; -- used in contradistinction from penumbra. See Penumbra.
The central dark portion, or nucleus, of a sun spot.