1. [n]  something existing in perception only; "a ghostly apparition at midnight"
2. [n]  a ghostly appearing figure; "we were unprepared for the apparition that confronted us"
3. [adj]  something apparently sensed but having no physical reality; "seemed to hear faint phantom bells"; "the amputee's illusion of a phantom limb"

Phantom
Description not available.

more details ...

1. \Phan"tom\, a.
   Being, or of the nature of, a phantom.
         Phantom isles are floating in the skies. --B. Taylor.
   

2. \Phan"tom\, n. [OE. fantome, fantosme, fantesme, OF.
   fant[^o]me, fr. L. phantasma, Gr. ?, fr. ? to show. See
   {Fancy}, and cf. {Pha["e]ton}, {Phantasm}, {Phase}.]
   That which has only an apparent existence; an apparition; a
   specter; a phantasm; a sprite; an airy spirit; an ideal
   image.
         Strange phantoms rising as the mists arise. --Pope.
         She was a phantom of delight.            --Wordsworth.
   {Phantom ship}. See {Flying Dutchman}, under {Flying}.
   {Phantom tumor} (Med.), a swelling, especially of the
      abdomen, due to muscular spasm, accumulation of flatus,
      etc., simulating an actual tumor in appearance, but
      disappearing upon the administration of an an[ae]sthetic.