hallucination
n. a false sensory perception that has a compelling sense of reality despite the absence of an external stimulus. It may affect any of the senses, but auditory hallucinations and visual hallucinations are most common. Hallucinations are typically a symptom of a psychotic disorder, particularly schizophrenia, but also may result from substance use, neurological abnormalities, and other conditions. It is important to distinguish hallucinations from illusions, which are misinterpretations of real sensory stimuli.