Source : Webster's Revised Unabridged Dictionary (1913)

Buckle \Buc"kle\, v. t. [imp. & p. p. {Buckled}; p. pr. & vb. n.
   {Buckling}.] [OE. boclen, F. boucler. See {Buckle}, n.]
   1. To fasten or confine with a buckle or buckles; as, to
      buckle a harness.

   2. To bend; to cause to kink, or to become distorted.

   3. To prepare for action; to apply with vigor and
      earnestness; -- generally used reflexively

Buckle \Buc"kle\, n. [OE. bocle buckle, boss of a shield, OF.
   bocle, F. boucle, boss of a shield, ring, fr. L. buccula a
   little cheek or mouth, dim. of bucca cheek; this boss or knob
   resembling a cheek.]
   1. A device, usually of metal, consisting of a frame with one
      more movable tongues or catches, used for fastening things
      together, as parts of dress or harness, by means of a
      strap passing through the frame and pierced by the tongue.

   2. A distortion bulge, bend, or kink, as in a saw blade or a
      plate of sheet metal. --Knight.

   3. A curl of hair, esp. a kind of crisp curl formerly worn;
      also, the state of being curled.

            Earlocks in tight buckles on each side of a lantern
            face.                                 --W. Irving.

            Lets his wig lie in buckle for a whole half year.
                                                  --Addison.

   4. A contorted expression, as of the face. [R.]

            'Gainst nature armed by gravity, His features too in
            buckle see.                           --Churchill.

Buckle \Buc"kle\ (b[u^]k"k'l), v. i.
   1. To bend permanently; to become distorted; to bow; to curl;
      to kink.

            Buckled with the heat of the fire like parchment.
                                                  --Pepys.

   2. To bend out of a true vertical plane, as a wall.

   3. To yield; to give way; to cease opposing. [Obs.]

            The Dutch, as high as they seem, do begin to buckle.
                                                  --Pepys.

   4. To enter upon some labor or contest; to join in close
      fight; to struggle; to contend.

            The bishop was as able and ready to buckle with the
            Lord Protector as he was with him.    --Latimer.

            In single combat thou shalt buckle with me. --Shak.

   {To buckle to}, to bend to; to engage with zeal.

            To make our sturdy humor buckle thereto. --Barrow.

            Before buckling to my winter's work.  --J. D.
                                                  Forbes.

Source : WordNet®

buckle
     v 1: fasten with a buckle or buckles [syn: {clasp}] [ant: {unbuckle}]
     2: fold or collapse; "His knees buckled" [syn: {crumple}]
     3: bend out of shape, as under pressure or from heat; "The
        highway buckled during the heatwave" [syn: {heave}, {warp}]

buckle
     n 1: fastener that fastens together two ends of a belt or strap;
          often has loose prong
     2: a shape distorted by twisting or folding [syn: {warp}]