In
woodworking and
construction, 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, and
spikes.