The Collaborative International Dictionary of English v.0.48:

Phantom \Phan"tom\, n. [OE. fantome, fantosme, fantesme, OF.
   fant[^o]me, fr. L. phantasma, Gr. fa`ntasma, fr. fai`nein 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.
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         Strange phantoms rising as the mists arise. --Pope.
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         She was a phantom of delight.            --Wordsworth.
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   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.
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