The Collaborative International Dictionary of English v.0.48:

Caryopsis \Car`y*op"sis\, n.; pl. Caryopses. [NL., fr. gr. ?
   hut, kernel + ? sight, form.] (Bot.)
   A one-celled, dry, indehiscent fruit, with a thin membranous
   pericarp, adhering closely to the seed, so that fruit and
   seed are incorporated in one body, forming a single grain, as
   of wheat, barley, etc.
   [1913 Webster]