1789, "sitting, session," as of a learned society, from French séance "a sitting," from seoir "to sit," from Latin sedere (see sedentary). Meaning "spiritualistic session" first recorded 1845.
(French: "sitting"), in occultism, meeting centred on a medium (q.v.), who seeks to communicate with spirits of the dead. Because strong light is said to hinder communication, a seance usually takes place in darkness or subdued light. It generally involves six or eight persons, who normally form a circle and hold hands