Hesperidium

from The Collaborative International Dictionary of English v.0.48

Hesperidium \Hes`pe*rid"i*um\, n. [NL. So called in allusion to
   the golden apples of the Hesperides. See {Hesperides}.]
   (Bot.)
   A large berry with a thick rind, as a lemon or an orange.
   [1913 Webster]