on edge

from The Collaborative International Dictionary of English v.0.48
Edge \Edge\ ([e^]j), n. [OE. eg, egge, AS. ecg; akin to OHG.
   ekka, G. ecke, Icel. & Sw. egg, Dan. eg, and to L. acies, Gr.
   'akh` point, Skr. a[,c]ri edge. [root]1. Cf. {Egg}, v. t.,
   {Eager}, {Ear} spike of corn, {Acute}.]
   1. The thin cutting side of the blade of an instrument; as,
      the edge of an ax, knife, sword, or scythe. Hence,
      (figuratively), That which cuts as an edge does, or wounds
      deeply, etc.
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            He which hath the sharp sword with two edges. --Rev.
                                                  ii. 12.
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            Slander,
            Whose edge is sharper than the sword. --Shak.
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   2. Any sharp terminating border; a margin; a brink; extreme
      verge; as, the edge of a table, a precipice.
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            Upon the edge of yonder coppice.      --Shak.
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            In worst extremes, and on the perilous edge
            Of battle.                            --Milton.
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            Pursue even to the very edge of destruction. --Sir
                                                  W. Scott.
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   3. Sharpness; readiness or fitness to cut; keenness;
      intenseness of desire.
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            The full edge of our indignation.     --Sir W.
                                                  Scott.
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            Death and persecution lose all the ill that they can
            have, if we do not set an edge upon them by our
            fears and by our vices.               --Jer. Taylor.
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   4. The border or part adjacent to the line of division; the
      beginning or early part; as, in the edge of evening. "On
      the edge of winter." --Milton.
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   {Edge joint} (Carp.), a joint formed by two edges making a
      corner.

   {Edge mill}, a crushing or grinding mill in which stones roll
      around on their edges, on a level circular bed; -- used
      for ore, and as an oil mill. Called also {Chilian mill}.
      

   {Edge molding} (Arch.), a molding whose section is made up of
      two curves meeting in an angle.

   {Edge plane}.
      (a) (Carp.) A plane for edging boards.
      (b) (Shoemaking) A plane for edging soles.

   {Edge play}, a kind of swordplay in which backswords or
      cutlasses are used, and the edge, rather than the point,
      is employed.

   {Edge rail}. (Railroad)
      (a) A rail set on edge; -- applied to a rail of more depth
          than width.
      (b) A guard rail by the side of the main rail at a switch.
          --Knight.

   {Edge railway}, a railway having the rails set on edge.

   {Edge stone}, a curbstone.

   {Edge tool}.
      (a) Any tool or instrument having a sharp edge intended
          for cutting.
      (b) A tool for forming or dressing an edge; an edging
          tool.

   {To be on edge},
      (a) to be eager, impatient, or anxious.
      (b) to be irritable or nervous.

   {on edge},
      (a) See {to be on edge}.
      (b) See {to set the teeth on edge}.

   {To set the teeth on edge},
      (a) to cause a disagreeable tingling sensation in the
          teeth, as by bringing acids into contact with them.
          [archaic] --Bacon.
      (b) to produce a disagreeable or unpleasant sensation; to
          annoy or repel; -- often used of sounds; as, the
          screeching of of the subway train wheels sets my teeth
          on edge.
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