Contrary to popular belief, it isn't just divining through the dead. Necromancy is when you work with the dead to learn things. You can divine, send them for protection purposes or curses, and so on. ;
lonely considering necromancy as a art to reanimate the dead is silly but one can conjure the dead and get answers from them. This is why Necro (Dead) and Mancy (Divination) means to seek answers from the dead nothing to do with summoning skeletons