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.
The party is walking through the forest at night when they come upon a clearing. Half a dozen black-robed corpses lie scattered across the ground, and a pentagram of blood is shoddily drawn in the dirt.
It seems these people summoned something they could not control. Whether or not the demon returns is up to the GM, but it would be just as rich if the demon never returned, and for the rest of the night, every stray sound or odd shadow will be jumped at!