Epicarp

Epicarp, the outer layer in true fruits such as the drupe. It may be smooth and polished, so as to shoot moisture, as in the cherry; glaucous, with a waxy bloom, as in the plum; woolly, as in the peach; or leathery, as in the orange; separable, as in these cases; or less so, as in the lemon. The term is often loosely extended to the outer layer of such receptacular structures, or "inferior" fruits, as the apple or cucumber.