hallucination

hal·lu·ci·na·tion

noun \hə-ˌlüs-^ən-ˈā-shən\

Definition of HALLUCINATION

1

: a perception of something (as a visual image or a sound) with no external cause usually arising from a disorder of the nervous system (as in delirium tremens or in functional psychosis without known neurological disease) or in response to drugs (as LSD)—compare delusion 2, illusion 2a

2

: the object of a hallucinatory perception