Necromancy (/ˈnɛkrɵˌmænsi/) is a claimed form of magic involving communication with the deceased – either by summoning their spirit as an apparition or raising them bodily – for the purpose of divination, imparting the means to foretell future events or discover hidden knowledge. The term may sometimes be used in a more general sense to refer to black magic or witchcraft.

The word "necromancy" is adapted from Late Latin necromantia, itself borrowed from post-Classical Greek νεκρομαντεία (nekromanteía), a compound of Ancient Greek νεκρός (nekrós), "dead body", and μαντεία (manteía), "prophecy or divination"; this compound form was first used by Origen of Alexandria in the 3rd century CE. The Classical Greek term was ἡ νέκυια (nekyia), from the episode of the Odyssey in which Odysseus visits the realm of the dead, νεκυομαντεία in Hellenistic Greek, rendered as necyomantīa in Latin, and as necyomancy in 17th century English.

In medieval Latin and English texts the variant nigromantia, "nigromancy", is found. This form arose when writers of that era replaced the unfamiliar Greek word element necro- with the better-known Latin nigro-, "black". In Renaissance magic, nigromancy (as necromancy was often called during that period due to its presumed association with black magic) was classified foremost among seven "forbidden arts", all of them methods of divination.