Fastener

A fastener is a mechanical component, or set of components, used to hold together two or more pieces of material. Fasteners vary from the simple nail in wood, to complex, multiple subcomponent systems used for extremely complex engineering problem. Some fasteners, such as screws often are removable, while others, such as nails or rivets are not. Some types, such as hinges are intended to allow controlled movement of the fastened pieces, while others are designed to hold the pieces in a rigid relationship.

Many fasteners use purely mechanical principles, but some will use chemical adhesives to add strength. They may also be used to hold pieces together so a more fundamental bonding (mechanical) technique can be used, such as welding, soldering, or brazing.