A nail is a pin-shaped object of metal (or wood, called a treenail or "trunnel") which is used as a fastener, as a peg to hang something, or sometimes as a decoration.Generally, nails have a sharp point on one end and a flattened head on the other, but headless nails are available. Nails are made in a great variety of forms for specialized purposes. The most common is a wire nail. Other types of nails include pins, tacks, brads, spikes, and cleats.
Nails are typically driven into the workpiece by a hammer, a pneumatic nail gun, or a small explosive charge or primer. A nail holds materials together by friction in the axial direction and shear strength laterally. The point of the nail is also sometimes bent over or clinched after driving to prevent pulling out.
As the name implies, wire nails are formed from wire. Usually coils of wire are drawn through a series of dies to reach a specific diameter, then cut into short rods that are then formed into nails. The nail tip is usually cut by a blade; the head is formed by reshaping the other end of the rod under high pressure. Other dies are used to cut grooves and ridges. Wire nails were also known as "French nails" for their country of origin.
Nails went from being rare and precious to being a cheap mass-produced commodity. Today almost all nails are manufactured from wire, but the term "wire nail" has come to refer to smaller nails, often available in a wider, more precise range of gauges than is typical for larger common and finish nails.