The Collaborative International Dictionary of English v.0.48:

Cordiform \Cor"di*form\ (k[^o]r"d[i^]*f[^o]rm), a. [L. cor,
   cordis, heart + -form, cf. F. cordiforme.]
   Heart-shaped. --Gray.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cordiform
    adj 1: (of a leaf) shaped like a heart [syn: cordate, heart-
           shaped, cordiform]