Nut lock

Nut \Nut\ (n[u^]t), n. [OE. nute, note, AS. hnutu; akin to D.
   noot, G. nuss, OHG. nuz, Icel. hnot, Sw. n["o]t, Dan.
   n["o]d.]
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   1. (Bot.) The fruit of certain trees and shrubs (as of the
      almond, walnut, hickory, beech, filbert, etc.), consisting
      of a hard and indehiscent shell inclosing a kernel.
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   2. A perforated block (usually a small piece of metal),
      provided with an internal or female screw thread, used on
      a bolt, or screw, for tightening or holding something, or
      for transmitting motion. See Illust. of 1st {Bolt}.
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   3. The tumbler of a gunlock. --Knight.
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   4. (Naut.) A projection on each side of the shank of an
      anchor, to secure the stock in place.
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   5. pl. Testicles. [vulgar slang]
      [PJC]

   {Check nut}, {Jam nut}, {Lock nut}, a nut which is screwed up
      tightly against another nut on the same bolt or screw, in
      order to prevent accidental unscrewing of the first nut.
      

   {Nut buoy}. See under {Buoy}.

   {Nut coal}, screened coal of a size smaller than stove coal
      and larger than pea coal; -- called also {chestnut coal}.
      

   {Nut crab} (Zool.), any leucosoid crab of the genus {Ebalia}
      as, {Ebalia tuberosa} of Europe.

   {Nut grass} (Bot.), See {nut grass} in the vocabulary.

   {Nut lock}, a device, as a metal plate bent up at the
      corners, to prevent a nut from becoming unscrewed, as by
      jarring.

   {Nut pine}. (Bot.) See under {Pine}.

   {Nut rush} (Bot.), a genus of cyperaceous plants ({Scleria})
      having a hard bony achene. Several species are found in
      the United States and many more in tropical regions.

   {Nut tree}, a tree that bears nuts.

   {Nut weevil} (Zool.), any species of weevils of the genus
      {Balaninus} and other allied genera, which in the larval
      state live in nuts.
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