Entity — A disembodied "consciousness" commonly referred to as a ghost, spirit or (if of an apparently malicious or resentful nature) demon.

EVP — Electronic Voice Phenomena: disembodied "voices" and sounds imprinted on audio recording devices.

Exorcism — Ceremonial expulsion of invading spiritual/demonic entities from a person or dwelling.

Floating Orb —  Spherical image, usually translucent white though sometimes of a reddish or bluish hue, which inexplicably registers on film and videotape.

Ghost — Image of a person witnessed after his/her death, reflecting the appearance of the living, physical body yet less substantial. These forms often seem to exist in a dreamlike state of semi-awareness, and are sometimes cognizant of their human observers.

Haunting — Manifestation of a ghostly presence, attached to a specific locale.

Intelligent Haunting — A haunting that knows you're there and interacts with you.

Materialization — When a ghost appears; can be sudden or gradual, indistinct or seemingly quite solid.

Residual Haunting — Psychic imprint of a scene that is repeatedly played out, and in which the witness of the phenomenon essentially is peering into the past. The ghostly participants of these time-displacements often seem unaware of their living observers

Vortex — A gateway that opens from the spirit world, like a rip in our dimension, and lets entities from the other side enter our world.