The term incoherent tinnitus comes from the Latin words in (not), cohaerens (coherent), and tinnire (to ring). It refers to a type of" tinnitus (i.e. 'ringing in the ears') in which the sound involved is perceived in the form of two distinct stimuli rather than the single, centred, auditory percept that characterizes "coherent tinnitus. As to its pathophysiology, incoherent tinnitus is associated primarily with peripheral (i.e. cochlear) lesions.
References
Henry, J.A., Dennis, K.C., Schechter, M.A. (2005). General review of tinnitus. Prevalence, mechanisms, effects, and management. Journal of Speech, Language, and Hearing Research, 48, 1204-1235.
Dictionary of Hallucinations. J.D. Blom. 2010.