Botanists classify the coconut as a fibrous, one-seeded drupe. A drupe is a fruit that has a hard cover surrounding the seed, for example, peaches or olives.
The word coconut is confusing because it implies that it is a nut. A strictly defined nut is a one-seeded fruit that releases its seed when the outer covering decays or is digested by an animal. A coconut could be considered a nut, although it could also be considered a fruit or a seed.
The coconut has three layers: the exocarp, the mesocarp and the endocarp. By the time a coconut makes it to market, the exocarp and mesocarp have been removed, but they are not discarded. Every part of the coconut is used to produce not only food and drink but fiber and fuel as well.