The term is archaic, calling upon the ancient language of the magi, and those versed in the eldritch arts. In the more vulgar argot, terms such as scrying room and equally mundane names are bandied about. The fact that such limited terms are used to describe the proper mystic's psychomanteum demonstrates how little they actually know about what occurs within.
A huge moon, with a three-coned volcano which can be seen from the planet when it erupts and is taken for an omen. The planet, smaller than the moon, orbits it, and the planet in turn is orbited by a very small but very hot and bright ball of flame.