The Collaborative International Dictionary of English v.0.48:

Exocarp \Ex"o*carp\, n. [Exo- + Gr. ? fruit.] (Bot.)
   The outer portion of a fruit, as the flesh of a peach or the
   rind of an orange. See Illust. of Drupe.
   [1913 Webster]

WordNet (r) 3.0 (2006):

exocarp
    n 1: outermost layer of the pericarp of fruits as the skin of a
         peach or grape [syn: epicarp, exocarp]