Auditory Hallucination or Paracusia is a form of hallucination that involves perceiving sounds without auditory stimulus. A common is hearing one or more talking voices which is associated with psychotic disorders such as schizophrenia or mania. Hallucination, itself, is the most common feature of perceiving the wrong stimulus or to the better word perception of the absence stimulus.Here we will discuss four definitions of hallucinations:1. Perceiving of a stimulus without the presence of any subject2. hallucination proper which are the wrong perceptions that are not the falsification of real perception, Although manifest as a new subject and happen along with and synchronously with a real perception3. hallucination is an out-of-body perception which has no accordance with a real subject In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid, substantial, and located in external objective space. We are going to discuss it in details here.