Paranormal: The realm of occurrences and phenomena removed from those to which people are accustomed and comprehend, and presently uncategorized by standard academia; beyond the range of normal experience or scientific explanation.
Apparition: a ghostly appearing figure.
Ghost: The image of a person witnessed after his/her death, reflecting the appearance of the living, physical body yet less substantial. These forms often seem to exist in a dream-like state of semi-awareness, at times though not always cognizant of their human observers.
Haunting: The manifestation of a ghostly presence, or presences, attached to a specific locale. Hauntings can be categorized into four (usually) distinct types, these being Intelligent (responsive), Poltergeist (likely initiated by pent-up stress on a subconcious level), Residual (replay) and Demonic (non-human origin).
Residual (Haunting): Psychic imprint of a scene which is repeatedly played out, where the witness of such phenomenon essentially is peering into the past. The ghostly participants of these time-displacements often seem unaware of their living observers.
Orb: a ball of energy that can be seen on camera or by the human eye; orbs move quickly and some say that an orb is a ghost trying to manifest it's self.