Word Origin & History
1604, "deceive," from L. alucinatus, later hallucinatus, pp. of alucinari "wander (in the mind), dream," probably from Gk. alyein, Attic halyein "be distraught," probably related to alasthai "wander about." The L. ending probably was influenced by vaticinari "to prophecy," also "to rave." Sense of "to
have illusions" is from 1652. Hallucination in the pathological/psychological sense of "seeing or hearing something which is not there" is first recorded 1646; distinct from illusion in not necessarily involving a false belief. Hallucinogen "drug which induces hallucinations" is first recorded 1954; hallucinogenic (adj.) in this sense is from 1952.