Source : Webster's Revised Unabridged Dictionary (1913)

Diuresis \Di`u*re"sis\, n. [NL. See {Diuretic}.] (Med.)
   Free excretion of urine.

Source : WordNet®

diuresis
     n : increased secretion of urine; if not due to increased liquid
         intake or to the action of a diuretic drug it can be a
         symptom of diabetes mellitus