An apparition (from the Latin apparers, to appear) is in its literal sense merely an appearance, that is, a sense-percept of any kind, but in every-day usage the word has a more restricted meaning and is used only to denote an abnormal or superabnormal appearance or percept, which cannot be referred to any natural objective cause. Taken in this sense the word covers all visionary appearances, hallucinations, clairvoyance, and similar unusual perceptions. ‘Apparition’ and ‘ghost’ are frequently used as synonymous terms, though the former is, of course, of much wider significance. A ghost is a visual apparition of a deceased human being, and the term implies that it is the spirit of the person it represents. Apparitions of animals and of inanimate objects are also sufficiently frequent. Not all apparitions take visual form, of course; many hauntings have been reported wherein the persons involved experienced certain sounds and smells, and even – in the case of the spiritualist mediums who brought forth ectoplasm – apparitions of the tactile variety.