ferrule

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A metal ring or cap placed around a pole or shaft for reinforcement or to prevent splitting.
• noun A bushing used to secure a pipe joint.

from The Century Dictionary.

• noun See ferule.
• noun A ring or cap of metal put on a column, post, or staff, as on the lower end of a cane or an umbrella, to strengthen it or prevent it from wearing or splitting.
• noun A ring sliding on the shaft of a spear and holding firmly to it the long tangs of the head; also, a ring or socket protecting the butt-end of a spear-shaft. The latter was also used as a weapon, or, when of a chisel form, as a tool. Compare celt.
• noun 3. In steam-boilers, a bushing for expanding the end of a flue.
• noun 4. The frame of a slate.
• noun 5 Anything like a ferrule (in sense 1) in form or position.

from the GNU version of the Collaborative International Dictionary of English.

• noun A ring or cap of metal put round a cane, tool, handle, or other similar object, to strengthen it, or prevent splitting and wearing.
• noun (Machinery) 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.
• noun (Steam Boilers) A bushing for expanding the end of a flue to fasten it tightly in the tube plate, or for partly filling up its mouth.
• noun (Chemistry) A bushing used at the joints of metal tubing in HPLC equipment to make a tight seal.
• noun (Fishing) One of several small rings at the top of a casting rod which holds the fishing line.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A metal band or cap placed around a shaft to reinforce it or to prevent splitting.
• noun A bushing for securing a pipe joint.
• noun A metal sleeve placed inside a gutter at the top.
• noun In billiards, the plastic band attaching the tip to the cue.
• noun In painting, the pinched metal band which holds the bristles of a brush to the shaft.
• noun On an ice axe, the metal spike at the end of the shaft.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a metal cap or band placed on a wooden pole to prevent splitting