from The American Heritage® Dictionary of the English Language, 4th Edition
- intransitive v. To make an abrupt, sharp sound, as in the collision of two hard surfaces.
- intransitive v. To chatter thoughtlessly or at length.
- intransitive v. To cackle or cluck, as a hen.
- transitive v. To cause to make an abrupt, sharp sound.
- n. A clacking sound: the clack of an old-fashioned typewriter.
- n. Something that makes a clacking sound.
- n. Thoughtless, prolonged talk; chatter.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. an abrupt, sharp sound, especially one made by two hard objects colliding repetitively; a clatter; in sound, midway between a click and a clunk
- n. Anything that causes a clacking noise, such as the clapper of a mill, or a clack valve.
- n. chatter; prattle
- v. to make such a sound
- v. to chatter or babble
from the GNU version of the Collaborative International Dictionary of English
- intransitive v. To make a sudden, sharp noise, or a succesion of such noises, as by striking an object, or by collision of parts; to rattle; to click.
- intransitive v. To utter words rapidly and continually, or with abruptness; to let the tongue run.
- transitive v. To cause to make a sudden, sharp noise, or succession of noises; to click.
- transitive v. To utter rapidly and inconsiderately.
- n. A sharp, abrupt noise, or succession of noises, made by striking an object.
- n. Anything that causes a clacking noise, as the clapper of a mill, or a clack valve.
- n. Continual or importunate talk; prattle; prating.
from The Century Dictionary and Cyclopedia
- To make a quick sharp noise, or a succession of sharp sounds, as by striking or cracking; crack; rattle; snap.
- To utter sounds or words rapidly and continually, or with sharpness and abruptness; let the tongue run or rattle.
- To cause to make a sharp, short, snapping sound; rattle; clap: as, to clack two pieces of wood together.
- To speak without thought; rattle out.
- n. A sharp, repeated, rattling sound; clatter: as, the clack of a mill.
- n. In a grist-mill: That part of the mill that strikes the hopper, to move or shake it, for discharging its contents.
- n. A bell that rings when more corn is required to be put in the hopper.
- n. A valve of a pump.
- n. A ball-valve connected with the boiler of a locomotive. See ball-ralve and clack-box, 2.
- n. A kind of small windmill with a clapper, set on the top of a pole to frighten away birds. Also called clack-mill, and formerly clacket.
- n. Continual talk; prattle; gossip; tattle.
- To cluck or cackle, as a hen.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- v. speak (about unimportant matters) rapidly and incessantly
- n. a sharp abrupt noise as if two objects hit together; may be repeated
- n. a simple valve with a hinge on one side; allows fluid to flow in only one direction
- v. make a rattling sound
- v. make a clucking sounds, characteristic of hens
Middle English clakken, from Old Norse klaka, of imitative origin.(American Heritage® Dictionary of the English Language, Fourth Edition)
Compare French claque ("a slap or smack"). (Wiktionary)