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
• Abnormally small production of urine

WordNet Word definitions in WordNet
n. 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

Wikipedia Word definitions in Wikipedia
Oliguria or hypouresis (both names from roots meaning "not enough urine") is the low output of urine . In humans, it is clinically classified as an output more than 80 ml/day but less than 400ml/day. The decreased output of urine may be a sign of dehydration ...

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1843, from oligo- "small, little," + -uria , from Greek ouron "urine" (see urine ).

Wiktionary Word definitions in Wiktionary
n. (context medicine English) A decreased production in the volume of urine.