ferrule

Ferrule is a word for a simple metal band or cap of great versatility. The ferrule is ubiquitous. It is the cap at the end of a cane or crutch, a chair or table leg; it is the point or knob at the hub of an umbrella; it fits together tubes and pipes and binds paintbrush handles to bristles and pencils to erasers. In Middle English this universal thingamajig was called a verrel. That word commonly referred to the strengthening bands or rings of iron used to prevent the splitting or wear of the wooden shafts of implements. The name evolved from Middle French virelle and Old French virol and ultimately from Latin viriola, meaning "small bracelet." The "f" spelling of today's ferrule was influenced by ferrum, the Latin word for "iron."