A hammer is a tool that strikes an object to move or deform it. It is most commonly used to nail, correct, or knock objects apart. Hammers come in a variety of forms, the common ones being a handle and a top.
One side of the top is flat to strike, and the other side is a hammer. The shape of the hammer head can be like a sheep horn or a wedge, and its function is to pull out nails. There is also a round-headed hammer head.