phantasma

from WordNet (r) 3.0 (2006)

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

from The Collaborative International Dictionary of English v.0.48

Phantasma \Phan"tas"ma\, n. [L.]
   A phantasm.
   [1913 Webster]