Source : Webster's Revised Unabridged Dictionary (1913)

Phantom \Phan"tom\, a.
   Being, or of the nature of, a phantom.

         Phantom isles are floating in the skies. --B. Taylor.

Phantom \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.

Source : WordNet®

phantom
     n 1: a ghostly appearing figure; "we were unprepared for the
          apparition that confronted us" [syn: {apparition}, {phantasm},
           {phantasma}, {specter}, {spectre}]
     2: something existing in perception only; "a ghostly apparition
        at midnight" [syn: {apparition}, {phantasm}, {phantasma},
        {shadow}]

phantom
     adj : something apparently sensed but having no physical reality;
           "seemed to hear faint phantom bells"; "the amputee's
           illusion of a phantom limb"