Source : Webster's Revised Unabridged Dictionary (1913)

Spathe \Spathe\, n. [L. spatha, Gr. ?: cf. F. spathe. See
   {Spade} for digging.] (Bot.)
   A special involucre formed of one leaf and inclosing a
   spadix, as in aroid plants and palms. See the Note under
   {Bract}, and Illust. of {Spadix}.

   Note: The name is also given to the several-leaved involucre
         of the iris and other similar plants.

Source : WordNet®

spathe
     n : a conspicuous bract surrounding or subtending a spadix or
         other inflorescence