Wiktionary
psychomanteum
alt. a mirrored room specially set up for communication with the spirit realm n. a mirrored room specially set up for communication with the spirit realm
Wikipedia
Psychomanteum
In parapsychology and spiritualism, a psychomanteum is a small, enclosed area set up with a comfortable chair, dim lighting, and a mirror angled so as not to reflect anything but darkness intended to communicate with spirits of the dead.