In botany, a caryopsis is a type of simple dry fruit — one that's monocarpelate (formed from a single carpel) and indehiscent (not opening at maturity) and resembles an achene, except that in a caryopsis the pericarp is fused with the thin seed coat. The caryopsis is popularly called a grain and is the fruit typical of the family Poaceae (or Gramineae), such as wheat, rice, and corn. The term grain is also used in a more general sense as synonymous with cereal (as in "cereal grains", wh… (More on Caryopsis)