pericarp
From The Oxford Companion to Beer
constitutes remains of the ovary wall that surrounds the embryo and endosperm in cereals. In cereals, such as barley, the pericarp is fused with the testa (seed coat) to form a thin layer that sits immediately below the husk encompassing the embryo, aleurone layer, and endosperm. The pericarp/testa may be revealed in barley by gently stripping the husk from the grain to show the slightly shiny skin of the grain. With cereals such as hull- less barley and wheat, the husk is removed during the threshing phase of harvesting to leave the grain covered by the pericarp/testa.
The role of the pericarp, particularly with hull-less cereals, is to protect the nutrient-rich endosperm, aleurone layer, and embryo from soil microbes.
This definition is from The Oxford Companion to Beer, edited by Garrett Oliver. © Oxford University Press 2012.