Source : Webster's Revised Unabridged Dictionary (1913)

Perisperm \Per"i*sperm\, n. [F. p['e]risperme. See {Peri-}, and
   {Sperm}.] (Bot.)
   The albumen of a seed, especially that portion which is
   formed outside of the embryo sac. -- {Per`i*sper"mic}, a.

Source : WordNet®

perisperm
     n : the nutritive tissue outside the sac containing the embryo
         in some seeds