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 follow string of Mirror-folk evolutions, Mihradhz, Mihrral, and Mihradamagus, are collectively known as The Mirr. They are all curious and slightly annoying, each in their own way. They advance through their lives by pestering the rare mortals who visit their plane.
Appearing a small ballista bolt, this ‘bolt’ is actually an arrow used by a god from a long-dead pantheon. Some sages theorize it was a weapon crafted by Loki to slay the world tree. Why it was never used escapes them however.
The spear has a divine-level anti-plant effect. When driven into the soil point first, a ever widening circle of destruction radiates out from the point, killing any plant material. Perfect for holding a kingdom’s food supply for ransom.
How far it extends depends of course on the GM, of course.