Ghost

1. The spirit; the soul of man.
2. Any faint shadowy semblance; an unsubstantial image; a phantom; a glimmering. Some people believe in ghosts.
3. A false image formed in a telescope, camera, or other optical device by reflection from the surfaces of one or more lenses. The reflection reminded her of a ghost.
4. The disembodied soul; the soul or spirit of a deceased person. Some ghosts haunt the house they died in.