Drupe, a succulent fruit composed of one carpel, superior, and containing one, or rarely two, seeds. It is characteristic of the sub-order Drupaceae of the Rosaceae, the "stone fruits," such as plums, cherries, apricots, peaches, etc., and has a pericarp (q.v.) of three distinct layers: the epicarrp or skin, the mesocarp, generally fleshy, and the endocarp, or stone, containing the seed ("kernel"). The epicarp may be glossy, as in cherries; glaucous, as in plums; or woolly, as in peaches. The term is often loosely used of somewhat similar fruits, such as the syncarpous olive, the date, in which the "stone" is a seed, and the walnut, which is inferior and bi-carpellary.