One of a pair of bean-shaped organs at the back of the abdomen (on each side of the spine) that maintain the balance of water and minerals in the body, play a role in regulating blood pressure, produce certain hormones, filter waste from the blood and produce urine.

Urine made in the kidneys passes through the ureters to the bladder.

Renal means referring to or having to do with the kidneys, as in renal failure.