A ghost, sometimes known as a spectre or specter, phantom,apparition, spirit, spook, or haunt, is the soul or spirit of a dead person or animal that can appear in visible form to the living. Descriptions of the apparition 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. 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, ghost trains, ghost ships, and even ghostanimals have also been recounted.
The belief in manifestations of the spirits of the dead is widespread, dating back to animism. Certain religious practices (some practices of spiritualism and ritual magic) are specifically designed to rest the spirits of the dead. A widespread belief concerning ghosts is that they are composed of a misty, airy, or subtle material. Anthropologists link this idea to early beliefs that ghosts were the spirit within the person, most noticeable in ancient cultures as a person's breath, which upon exhaling in colder climates appears visibly as a white mist. This belief may have also fostered the metaphorical meaning of "breath" in certain languages, such as the Latin spiritus and the Greek pneuma, which by analogy became extended to mean the soul. In the Bible, God is depicted as synthesising Adam, as a living soul, from the dust of the Earth and the breath of God.
In many traditional accounts, ghosts were often thought to be deceased people looking for vengeance, or imprisoned on earth for bad things they did during life. The appearance of a ghost has often been regarded as an omen or portent of death. Seeing one's own ghostly double or "fetch" is a related omen of death. Legends of ghost ships have existed since the 18th century; most notable of these is the Flying Dutchman, a legend dating back to the 1600's.