thumb|"Hamlet and his father's ghost" by Henry Fuseli (1780s drawing)

A ghost is popularly held to be the disembodied spirit or soul of a deceased person.http://www.parapsych.org/glossary_e_k.html#g Parapsychological Association, glossary of key words frequently used in parapsychology, Retrieved December 13 2006 Popularly described as insubstantial and partly transparent, ghosts are reported to haunt particular locations or people that they were associated with in life or at time of death.

Phantom armies, ghost-animals, ghost trains and phantom ships have also been reported.

A poll conducted in 2003 showed that more than half of adults in the United States believe in ghosts and/or demons.

Ghosts or similar paranormal entities appear in film, theatre, and literature; legends and myths, and some religions.

Etymology and Synonyms

The English word ghost continues Old English gást, hypothetical Common Germanic *gaisto-z. It is common to West Germanic, but lacking in North and East Germanic (the equivalent word in Gothic is ahma, Old Norse has andi m., önd f.). The pre-Germanic form would have been PIE: *ghoizdo-z, apparently from a root denoting "fury, anger", cognate to Sanskrit hedas "anger", reflected in Old Norse geisa "to rage". The Germanic word is recorded as masculine only, but likely continues a neuter s-stem. The original meaning of the Germanic word would thus have been an animating principle of the mind, in particular capable of excitation and fury (compare óðr). In Germanic paganism, "Germanic Mercury", and the later Odin, was at the same time the conductor of the dead and the "lord of fury" leading the Wild Hunt.

Besides denoting the human spirit or soul, both of the living and the deceased, the Old English word is used as a synonym of Latin spiritus also in the meaning of "breath, blast" from the earliest (9th century) attestations. It could also denote any good or evil spirit, i.e. angels and demons; the Anglo-Saxon gospel refers to the demonic possession of Matthew 12:43 as se unclæna gast. Also from the Old English period, the word could denote the spirit of God, viz. the "Holy Ghost". The now prevailing sense of "the soul of a deceased person, spoken of as appearing in a visible form" emerges in Middle English (14th century) only.

The synonym spook is also a Germanic word, although it was introduced into American English only in the 19th century, apparently as a loan from Low German spôk, of uncertain etymology. Alternate words in modern usage include spectre (from Latin spectrum), the Scottish wraith (of obscure origin), phantom (via French ultimately from Greek phantasma, compare fantasy) and apparition. The term shade in classical mythology translates Greek σκιά, or Latin umbra, in reference to the notion of spirits in the Greek underworld.