From Greek en, "in" plus gaster, "belly" plus mythos, "speech, talk"; which makes it the equivalent of the better known Latin ventriloquist, which itself comes from venter, "belly" plus loqui, "speak, talk".

Engastrimyth is rarely seen anymore and it refers to the soothsaying phenomenon of speaking without appearing to speak. It has been associated with prophetesses; such as, the famous Delphic Oracle, or with seers who acted as conveyors for the voice of someone beyond the grave; such as, the Biblical story of the Witch of Endor.