from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. The prominence of the dorsal aspect of a joint of a finger, especially of one of the joints connecting the fingers to the hand.
  • n. A rounded protuberance formed by the bones in a joint.
  • n. A cut of meat centering on the carpal or tarsal joint, as of a pig.
  • n. The part of a hinge through which the pin passes.
  • n. A sharp angle formed by the meeting of two surfaces, especially two ship's timbers.
  • n. Brass knuckles.
  • transitive v. To press, rub, or hit with the knuckles.
  • transitive v. To shoot (a marble) with the thumb over the bent forefinger.
  • knuckle down To apply oneself earnestly to a task.
  • knuckle under To yield to pressure; give in.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. Any of the joints between the phalanges of the fingers.
  • n. A mechanical joint.
  • n. A cut of meat.
  • n. The curved part of the cushion at the entrance to the pockets on a cue sports table.
  • v. To apply pressure, or rub or massage with one's knuckles.

from the GNU version of the Collaborative International Dictionary of English

  • n. The joint of a finger, particularly when made prominent by the closing of the fingers.
  • n. The kneejoint, or middle joint, of either leg of a quadruped, especially of a calf; -- formerly used of the kneejoint of a human being.
  • n. The joint of a plant.
  • n. The joining parts of a hinge through which the pin or rivet passes; a knuckle joint.
  • n. A convex portion of a vessel's figure where a sudden change of shape occurs, as in a canal boat, where a nearly vertical side joins a nearly flat bottom.
  • n. A contrivance, usually of brass or iron, and furnished with points, worn to protect the hand, to add force to a blow, and to disfigure the person struck; -- called also knuckle duster, knuckles or brass knuckles.
  • intransitive v. To yield; to submit; -- used with down, to, or under.
  • transitive v. To beat with the knuckles; to pummel.

from The Century Dictionary and Cyclopedia

  • To touch or strike with the knuckle; pommel.
  • To bend the knuckles; hold the knuckles (that is, the hand) close to the ground, in playing marbles: usually with down.
  • To apply one's self earnestly, as to a task; engage vigorously, as in work.
  • To submit, as in a contest; give up; yield.
  • To apply one's self earnestly.
  • n. The joint of a finger, especially that between the metacarpal bone and the first phalanx.
  • n. The knee or knee-joint.
  • n. A joint, especially of veal, consisting of the part of the leg called the knee. It is the part of the animal which corresponds to the hock of a horse, or the human heel, together with more or less of the leg above this joint.
  • n. The joint of a plant; a node.
  • n. A joint of cylindrical form, with a pin as axis, as that by which the straps of a hinge are fastened together.
  • n. In ship-building, an acute angle on some of the timbers.
  • n. plural Pieces of metal, usually brass (hence specifically known as brass knuckles), worn by lawless persons over the knuckles to protect them in striking a blow, and also to make a blow more effective. See knuckle-duster.
  • n. A sharply bent loop, as of intestine, especially when imprisoned, as in a hernia.
  • n. In mech., the swinging leaf or hook used for the coupling device in certain automatic car-couplings, particularly in the Janney or M. C. B. (master car-builders') type. A hole is usually provided in the knuckle so that the common link-coupling may be used with it.

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

  • n. a joint of a finger when the fist is closed
  • v. press or rub with the knuckles
  • v. shoot a marble while keeping one's knuckles on the ground


from The American Heritage® Dictionary of the English Language, 4th Edition

Middle English knokel.

from Wiktionary, Creative Commons Attribution/Share-Alike License

From the diminutive of a word for bone, found in German Knochen


  • Our "humble pie" is their "humble sandwich": people do actually use the expression "knuckle sandwich" to describe a punch here, and Obama's deal to raise the debt ceiling was unanimously panned as "a sugar-coated Satan sandwich". - Telegraph online, Daily Telegraph and Sunday Telegraph

  • Though it was well after midnight, everyone was hustled onto a bus for what she describes as a knuckle-biting three-hour trip to their scheduled destination.

    Tales From The Sardine Run

  • Of course they did not use what we call knuckle-dusters, nor did they even double their fists, except when moving round each other, and as "gloves" were unknown, they struck out with the hands half open, for they had no wish to bleed each other's noses or black each other's eyes for mere amusement.

    The Hot Swamp

  • I rarely write anything out longhand anymore, but the middle finger of my left hand still has a life-long callous alongside the top knuckle from a pen or pencil grinding into it. stennieville fjpoblam

    Loosen Up Your Writing Grip To Banish Pain | Lifehacker Australia

  • By walking upright over four million years ago, the earliest hominids were already on an evolutionary track separate from even chimps and gorillas, our nearest genetic cousins, who locomote with a different kind of gait known as knuckle-walking.

    Deepak Chopra: What We Don't Know Is Thrilling

  • It's so much a caricature of the Ugly American stereotype, has so many gaping holes and plain knuckle-headed bias in it that we assumed it was a joke, but since no Gotcha post from him follows (his post is dated June 12th), we are forced to assume he meant it.

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  • Although a knuckle is likely to carry a wound now and then, Jim keeps his hands very clean and the nails neatly trimmed.


  • In the hindquarter if the knuckle is limp, and the part under the kidney smells slightly disagreeable, avoid it.

    Confederate Receipt Book: A Compilation of over One Hundred Receipts, Adapted to the Times

  • (torn tissue in knuckle of left middle finger) is on the 15-day DL

  • [...] my non-halal post on the pork knuckle from the Bulgarian restaurant over at my other food [...]

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  • I am not an expert on anatomy or butchery but my sense is that the word knuckle seems to be more associated with human, veal and pig. I am not aware that one talks about beef knuckle, horse knuckle, deer knuckle or the joints of other animals as being knuckles. If this is true, the linguistic geography and specie or food-type associations would be a unique dimentsion to the use and meaning of this word. It is also one of the many kn/gn words that are associated with food, digestion, learning such as knowledgem gnaw, etc.

    September 4, 2009

  • Sounds like "naco," sort of "redneck" in Spanish. Makes my students laugh.

    July 4, 2007