thimble

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

• noun A hard, usually pitted cup worn for protection on the finger that pushes the needle in sewing.
• noun Any of various tubular sockets or sleeves in machinery.
• noun A metal ring fitted in an eye of a sail to prevent chafing.
• noun A metal ring around which a rope splice is passed.

from The Century Dictionary.

• noun An implement used for pushing the needle in sewing, worn on one of the fingers, usually the middle finger of the right hand.
• noun In mech., a sleeve, skein, tube, bushing, or ferrule used to join the ends of pipes, shafting, etc., or to fill an opening, expand a tube, cover an axle, etc. It is made in a variety of shapes, and is called thimble-joint, thimble-coupling, thimble-skein, etc. See cut under coupling.
• noun Nautical, an iron or brass ring, concave on the outside so as to fit in a rope, block-strap, cringle, etc., and prevent chafe, as well as to preserve shape; also, an iron ring attached to the end of drag-ropes.
• noun A ring or oval, made of steel with a concave section on the outside, and convex within, used to form the eye in the end of a wire rope when the latter is bent round the ring and the end spliced into the main part.
• noun 4. A cone of fat-free paper used in a fat-extraction apparatus.
• noun 5. A cup-shaped metal support for the handle of a tool in dental operations: it rests in the palm of the hand and is attached to a ring on the middle finger.
• noun 6. plural A trade-name for crude india-rubber from the lower Kongo and Loanda in small balls of a gray color, darker outside.

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

• noun 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.
• noun (Mech.) Any thimble-shaped appendage or fixure.
• noun A tubular piece, generally a strut, through which a bolt or pin passes.
• noun A fixed or movable ring, tube, or lining placed in a hole.
• noun A tubular cone for expanding a flue; -- called ferrule in England.
• noun (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.

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

• noun sewing A pitted, now usually metal, cap for the fingers, used in sewing to push the needle.
• noun A similarly shaped socket in machinery.
• noun A thimbleful.
• noun nautical A ring of metal or rope used in a ship's rigging; it is a protection against chafing.

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

• noun a small metal cap to protect the finger while sewing; can be used as a small container
• noun as much as a thimble will hold