A drupe is a type of fruit that has a single seed enclosed within a hard, stony endocarp, surrounded by a fleshy outer layer. Common examples of drupes include cherries, peaches, and mangoes. The structure of a drupe typically consists of three layers: the exocarp (outer skin), mesocarp (fleshy part), and endocarp (hard shell). Drupes are classified as a type of simple fruit, which means they develop from a single ovary of a flower. This unique structure allows for the protection of the seed while providing a nutritious and appealing fruit for animals, which helps in seed dispersal.