Necromancy
Necromancy (Greek nekros, dead + manteía, divination) is the practice of communicating with spirits of the dead to obtain knowledge of the future or hidden information. Practice documented since Mesopotamia and described in the Odyssey (Odysseus consulting Tiresias). Considered taboo in classical antiquity and forbidden in major Abrahamic religions.
Distinction from spiritism
Necromancy emphasizes the coercive/ritual aspect (forcing the spirit to appear); spiritism emphasizes voluntary communication through medium.