The term 'of kidneys' can be summarized by the word 'renal, ' which is a five-letter word. Renal refers to anything related to the kidneys, such as their anatomy, physiology, or diseases. The kidneys are two bean-shaped organs located in the abdomen that filter waste products from the blood and excrete them in the form of urine. They also help regulate blood pressure, electrolyte balance, and red blood cell production.