A séance or seance is an attempt to communicate with spirits. The word séance comes from the French word for "session", from the Old French seoir, "to sit". In French, the word's meaning is quite general: one may, for example, speak of "une séance de cinéma". In English, however, the word came to be used specifically for a meeting of people who are gathered to receive messages from ghosts or to listen to a spirit medium discourse with or relay messages from spirits. In modern English usage, participants need not be seated while engaged in a séance.

In folklore, a ghost is the soul or spirit of a dead person or non-human animal that is believed to be able to appear to the living. In ghostlore, descriptions of ghosts vary widely, from an invisible presence to translucent or barely visible wispy shapes to realistic, lifelike forms. The deliberate attempt to contact the spirit of a deceased person is known as necromancy, or in spiritism as a séance. Other terms associated with it are apparition, haunt, haint, phantom, poltergeist, shade, specter, spirit, spook, wraith, demon, and ghoul.