Actually, it can be all three. Botanically speaking, a coconut is a fibrous one-seeded drupe, which is a fruit with a hard stony covering enclosing the seed. A seed is the reproductive unit of a flowering plant. From a reproductive point of view, a seed has two basic parts: the embryo root (hypocotyl) and the embryo leaves (epicotyl). In the coconut’s case, if you look at one end of the coconut, you’ll see three pores (also called eyes). The coconut seed germinates and a shoot emerges from one of the pores. In addition to the plant in the seed, there is the endosperm or food to kick off the plant’s life. The endosperm is what makes up most of the seed and, in the coconut’s case, is the yummy white stuff we eat.

The word coconut itself can be misleading because “nut” is part of the word. A loose definition of nut is a one-seeded fruit, so one could argue on behalf of the coconut. However, a true nut, like the acorn, does not open at maturity to release its seeds. The seeds are released when the fruit wall decays or are digested by an animal.

The complete answer to this and many other “Everyday Mysteries” can be found in the Library’s Web pages of the same name. These mysteries deal with everyday phenomena often taken for granted, but each can be explained scientifically.