kidney

noun

Either one of a pair of organs in the dorsal region of the vertebrate abdominal cavity, functioning to maintain proper water and electrolyte balance, regulate acid-base concentration, and filter the blood of metabolic wastes, which are then excreted as urine.

The kidney of certain animals, eaten as food.

An excretory organ of certain invertebrates.

Temperament; kind.

In min., a concretion shaped like a kidney.