Main Entry: phan·tasm
Variant(s): also fan·tasm \ˈfan-ˌta-zəm\
Function: noun
Etymology: Middle English fantasme, from Anglo-French fantosme, fantasme, from Latin phantasma, from Greek, from phantazein to present to the mind — more at fancy
Date: 13th century

1 : a product of fantasy: as a : delusive appearance : illusion b : ghost, specter c : a figment...