The Collaborative International Dictionary of English v.0.48:

Lentiform \Len"ti*form\ (l[e^]n"t[i^]*f[^o]rm), a. [L. lens,
   lentis, lentil + -form: cf. F. lentiforme.]
   Lenticular.
   [1913 Webster]

WordNet (r) 3.0 (2006):

lentiform
    adj 1: convex on both sides; shaped like a lentil [syn:
           biconvex, convexo-convex, lenticular, lentiform]