Definitions for oliguria
abnormally small production of urine; can be a symptom of kidney disease or obstruction of the urinary tract or edema or an imbalance of fluids and electrolytes in the body
production of an abnormally small amount of urine
A decreased production in the volume of urine.
U.S. National Library of Medicine
Decreased URINE output that is below the normal range. Oliguria can be defined as urine output of less than or equal to 0.5 or 1 ml/kg/hr depending on the age.