Ferrule is a metal band or ring used to secure two objects together. It is commonly used in plumbing and electrical applications. The term ferrule can also refer to a metal cap that is placed on the end of a handle, such as a cane or umbrella. In the crossword puzzle, the solutions for ferrule are TIP (3 letters) and COLLET (6 letters). TIP refers to the metal cap that is placed on the end of a handle, while COLLET is a type of ferrule used to secure two objects together.