Kidney \Kid"ney\, n.; pl. Kidneys. [OE. kidnei, kidnere, from Icel. koi?r belly, womb (akin to Goth. gipus, AS. cwip womb) + OE. nere kidney; akin to D. nier, G. niere, OHG. nioro, Icel. n?ra, Dan. nyre, Sw. njure, and probably to Gr. (?) Cf. Kite belly.]

Source: Webster's Revised Unabridged Dictionary (1913)