'Ferrule' definitions:

Definition of 'ferrule'

noun

A metal cap or band placed on a wooden pole to prevent splitting [syn: ferrule, collet]

From: GCIDE

Ferrule \Fer"rule\ (f[e^]r"r[i^]l or f[e^]r"r[.u]l; 277), 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.] [Sometimes spelled ferule.]
1. 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]
2. (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. [PJC]
3. Hence: (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. [1913 Webster]
4. Hence: (Chemistry) A bushing used at the joints of metal tubing in HPLC equipment to make a tight seal. [PJC]
5. (Fishing) One of several small rings at the top of a casting rod which holds the fishing line. --RHUD [PJC]

From: GCIDE

Thimble \Thim"ble\, n. [OE. thimbil, AS. ??mel, fr. ??ma a thumb. [root]56. See Thumb.]
1. A kind of cap or cover, or sometimes a broad ring, for the end of the finger, used in sewing to protect the finger when pushing the needle through the material. It is usually made of metal, and has upon the outer surface numerous small pits to catch the head of the needle. [1913 Webster]
2. (Mech.) Any thimble-shaped appendage or fixure. Specifically: (a) A tubular piece, generally a strut, through which a bolt or pin passes. (b) A fixed or movable ring, tube, or lining placed in a hole. (c) A tubular cone for expanding a flue; -- called ferrule in England. [1913 Webster]
3. (Naut.) A ring of thin metal formed with a grooved circumference so as to fit within an eye-spice, or the like, and protect it from chafing. [1913 Webster]