n.1 the prediction of the future by the supposed communication with the dead.
2 witchcraft.
Derivatives:
necromancer n. necromantic adj.
Etymology: ME f. OF nigromancie f. med.L nigromantia changed (by assoc. with L niger nigri black) f. LL necromantia f. Gk nekromanteia (as NECRO-, -MANCY)