The Collaborative International Dictionary of English v.0.48:
Reniform \Ren"i*form\ (r?n"?-f?rm; 277), a. [L. renes kidneys + -form: cf. F. r['e]niforme.] Having the form or shape of a kidney; as, a reniform mineral; a reniform leaf. [1913 Webster] RenitenceWordNet (r) 3.0 (2006):
reniform adj 1: (of a leaf or bean shape) resembling the shape of kidney [syn: reniform, kidney-shaped]