means the branch of medicine devoted to the kidneys — their function, their diseases, and the delicate chemistry of filtering your blood.

from From Greek 'nephros,' meaning kidney, joined with '-logia,' the study of. The Greeks named the bean-shaped pair, and centuries later medicine borrowed the word wholesale; the same 'nephros' hides inside 'nephritis' and the now-archaic 'nephric.' Curiously, the Latin word for kidney, 'ren,' went its own way into English ('renal'), so the organ ended up with two ancestral tongues — Greek for the doctor's specialty, Latin for the adjective.