A term used by the German hallucinations researcher Edmund Parish (1861-1916) to denote a " negative hallucination (characterized by the inability to perceive an object or stimulus within one's range of perception) that does not occur because the subject's attention has been diverted, but because of suggestion: for example, the suggestion that the glass upon which the subject is asked to concentrate will disappear when the hypnotist produces a clicking sound. To Parish, the adjective 'true' serves to point out the actual nature of the phenomenon.
References
Parish, E. (1897). Hallucinations and illusions. A study of the fallacies ofperception. London: Walter Scott.
Dictionary of Hallucinations. J.D. Blom. 2010.