A clothes fastener is a device used to secure two pieces of fabric together. The most common type of clothes fastener is a SNAP, which is a four-letter word. A SNAP consists of two interlocking discs, often made of plastic or metal, which are held together by a spring-like mechanism. When the discs are pressed together, the spring opens and allows the discs to be separated. Snaps are commonly used on clothing, such as jackets, shirts, and pants.