The coconut is the fruit of the coconut palm. Coconut palms grow in tropical areas of the world along beaches. They like warm weather, regular rain and high humidity, which is why they grow well in the tropics.
You eat the flesh inside the coconut fruit, but there are many, many uses for the rest of the coconut palm. There are too many to list here, but they include: making rope and doormats from the outer shell of the nut; making bowls from the inner shell; and building houses from the trunk and branches of the palm tree.
Coconut is used in many different ways in a wide variety of foods. One you might recognise is simply dried, grated, and stuck to the outside of a lamington!