Source : Webster's Revised Unabridged Dictionary (1913)

Episperm \Ep"i*sperm\, n. [Pref. epi- + Gr. ? seed: cf. F.
   ['e]pisperme.] (Bot.)
   The skin or coat of a seed, especially the outer coat. See
   {Testa}.

Source : WordNet®

episperm
     n : protective outer layer of seeds of flowering plants [syn: {testa},
          {seed coat}]