Main Entry: kid·ney

Pronunciation: \ˈkid-nē\

Function: noun

Inflected Form(s): plural kidneys

Etymology: Middle English

Date: 14th century

1 a : one of a pair of vertebrate organs situated in the body cavity near the spinal column that excrete waste products of metabolism, in humans are bean-shaped organs about 4¹⁄₂ inches (11¹⁄₂ centimeters) long lying behind the peritoneum in a mass of fatty tissue, and consist chiefly of nephrons by which urine is secreted, collected, and discharged into a main cavity whence it is conveyed by the ureter to the bladder b : any of various excretory organs of invertebrate animals
2 : the kidney of an animal eaten as food
3 : sort or kind especially with regard to temperament <a nice helpful guy, of a different kidney entirely from the…Secret Police — Paula Lecler>