In Gnosis and Theosophy, eidolon is generally used to refer to the Astral Body. The word means "appearance, reflection of oneself in water or a mirror, also mental image, apparition, phantom;" eidolon also means “any material image, statue,” from eidos “form” from Latinized form of Greek -oeides, from eidos “form,” related to idein “to identify,” eidenai literally “to idein-tify, to recognize, mental perception.”
In ancient Greek literature, eidolon is used in relation with the astral form utilized by the dead that emulates their former physical appearance.
