nekyia

thumb|upright=1|The Shade of Tiresias Appearing to [[Odysseus during the Sacrifice (c. 1780-85), painting by Johann Heinrich Füssli, showing a scene from Book Eleven of the Odyssey]]

In ancient Greek cult practice and literature, a nekyia or nekya () is a "rite by which ghosts were called up and questioned about the future," i.e., necromancy. A nekyia is not necessarily the same thing as a katabasis. While they both afford the opportunity to converse with the dead, only a katabasis is the actual, physical journey to the underworld undertaken by several heroes in Greek and Roman myth.