In folklore and mythology, a ghost (sometimes known as a specter, phantom, apparition, poltergeist, spirit, spook, or haunt) is the soul or spirit of a dead person (human or animal) that can appear to the living. Descriptions of ghosts vary widely from an invisible presence to translucent or barely visible wispy shapes, to realistic, lifelike visions. The deliberate attempt to contact the spirit of a deceased person is known as necromancy, or in spiritism as a séance.
The belief in manifestations of the spirits of the dead is widespread, dating back to animism or ancestor worship in pre-literate cultures. Certain religious practices—funeral rites, exorcisms, and some practices of spiritualism and ritual magic—are specifically designed to rest the spirits of the dead. Ghosts are generally described as solitary essences that haunt particular locations, objects, or people they were associated with in life, though stories of phantom armies, trains, ships, and even the ghosts of animals have also been recounted.
In some fictional works, ghosts are a separate species of being, rather than the essence of a dead person. Many fantasy authors, Harry Turtledove included, have mixed and matched both kinds of ghosts, and/or invented even further varieties.
Ghosts haunted their living relatives in the land of Kudurru. They were not visible, but could be heard by the people who'd known them in life. Ghosts dwelt in the "symbolic world" more so than the material one. For example, while ghosts could not eat or drink, or even move objects, a ghost could "drink" from a largely empty glass so long as a living person had made a show of pretending to fill that glass.
Spirits were beings who could exist in the spirit world and the natural world as well. As their presence in the natural world was less solid, malefactors who sought to harm spirits had to either travel to the spirit world or find a spiritual weapon that could also work in the real world.
Ghosts were an integral part of the landscape in North Elabon. Travelers in the wilderness always brought along plenty of blood (of any animal) to placate the ghosts, so that the spirits would not harass or harm them.