either of two bean-shaped excretory organs that filter wastes (especially urea) from the blood and excrete them and water in urine; "urine passes out of the kidney through ureters to the bladder"
(cryogenics) the lowest temperature theoretically attainable (at which the kinetic energy of atoms and molecules is minimal); 0 Kelvin or -273.15 centigrade or -459.67 Fahrenheit