Source : Webster's Revised Unabridged Dictionary (1913)

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. --Gray.

Source : WordNet®

kidney-shaped
     adj : of a leaf or bean shape resembling the shape of kidney [syn:
            {reniform}]