A ferrule is a name for types of objects, generally used for fastening, joining, sealing or reinforcement. They are often narrow circular rings made from metal, or less commonly

Most ferrules consist of a circular clamp used to hold together and attach fibers, wires, or posts, generally by crimping, swagging, or otherwise deforming the ferrule to permanently tighten it onto the parts that it holds.

Steel ferrules have been specially developed for stainless steel wire ropes.