The Collaborative International Dictionary of English v.0.48:
Kidney-form \Kid"ney-form`\, Kidney-shaped \Kid"ney-shaped`\, a. Having the form or shape of a kidney; reniform; as, a kidney-shaped leaf; a kidney-shaped swimming pool. --Gray. [1913 Webster +PJC]WordNet (r) 3.0 (2006):
kidney-shaped adj 1: (of a leaf or bean shape) resembling the shape of kidney [syn: reniform, kidney-shaped]