What is the definition or description of: auditory hallucination?

Hallucination: In general, a hallucination is a perceptual experience in the absence of external stimuli. Hallucinations can occur in any sensory modality including auditory, visual, tactile, olfactory, and gustatory. Auditory hallucinations refer to the experience of "hearing" something in the absence of an external noise.

Hearing : By definition anauditory hallucination is hearing something in the environment that does not exist in reality. Auditory hallucinations are most often experienced by those suffering from schizophrenia.