—n. 1. a ring or cap, usually of metal, put around the end of a post, cane, or the like, to prevent splitting.
2. a short metal sleeve for strengthening a tool handle at the end holding the tool.
3. a bushing or adapter holding the end of a tube and inserted into a hole in a plate in order to make a tight fit, used in boilers, condensers, etc.
4. a short ring for reinforcing or decreasing the interior diameter of the end of a tube.
5. a short plumbing fitting, covered at its outer end and caulked or otherwise fixed to a branch from a pipe so that it can be removed to give access to the interior of the pipe.
6. Angling. a. either of two fittings on the end of a section of a sectional fishing rod, one fitting serving as a plug and the other as a socket for fastening the sections together.
b. one of two or more small rings spaced along the top of a casting rod to hold and guide the line.