ferrule

• POS: Noun, Verb (transitive)
• HYPHEN: fer=rule

CIDE DICTIONARY

ferrule, n. [Formerly verrel, F. virole, fr. L. viriola little bracelet, dim. of viriae, pl., bracelets; prob. akin to viere to twist, weave, and E. withe. The spelling with f is due to confusion with L. ferrum iron.].

•  A ring or cap of metal put round a cane, tool, handle, or other similar object, to strengthen it, or prevent splitting and wearing.  [1913 Webster]
•  Any of various circular or cylindrical metal objects used at joints in a tube, pipe, or rod, especially to assist making a tight seal at a joint.  [PJC]
•  A bushing for expanding the end of a flue to fasten it tightly in the tube plate, or for partly filling up its mouth.  [1913 Webster]
•  A bushing used at the joints of metal tubing in HPLC equipment to make a tight seal.  [PJC]
•  One of several small rings at the top of a casting rod which holds the fishing line.  [PJC]

OXFORD DICTIONARY

ferrule, n. (also ferrel)
1 a ring or cap strengthening the end of a stick or tube.
2 a band strengthening or forming a joint.

Etymology

earlier verrel etc. f. OF virelle, virol(e), f. L viriola dimin. of viriae bracelet: assim. to L ferrum iron