kidney

(KID-nee) One of a pair of organs in the abdomen. Kidneys remove waste from the blood (as urine), produce erythropoietin (a substance that stimulates red blood cell production), and play a role in blood pressure regulation.

(KID-nee): A bean-shaped organ that filters waste products from the body and forms urine that is passed into the bladder. Human beings are born with two kidneys, one on each side of the lower back.