eidolon

Etymology

From Ancient Greek εἴδωλον (eídōlon, “figure, representation”), from εἶδος (eîdos, “sight”), from εἴδω (eídō, “I see”). Doublet of idol, idolum, and idea.

noun

1. An image or representation of an idea; a representation of an ideal form; an apparition of some actual or imaginary entity, or of some aspect of reality.
   As a species it is extinct; as an eidolon it retains its corporeality – but only if maintained in a state of equipoise. 1936, Henry Miller, Black Spring
   It was not hard to forge her image, her "eidolon", in the grey gloom of the little church. 1974, Lawrence Durrell, Monsieur, Faber & Faber, published 1992, page 21
   Kit was sitting up staring into the dark at this eidolon, inelegantly turned out contrary to a whole raft of public-decency statutes, which had come monitory and breathing in to violate Kit's insomnia. 2006, Thomas Pynchon, Against the Day, Vintage, published 2007, page 697
2. A phantom, a ghost or elusive entity.
3. An unsubstantial image, spectre, phantom.