The Collaborative International Dictionary of English v.0.48:

Clamp \Clamp\ (kl[a^]mp), v. t. [imp. & p. p. Clamped
   (kl[a^]mt; 215) p. pr. & vb. n. Clamping.]
   1. To fasten with a clamp or clamps; to apply a clamp to; to
      place in a clamp.
      [1913 Webster]

   2. To cover, as vegetables, with earth. [Eng.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Clamp \Clamp\, n. [Prob. an imitative word. Cf. Clank.]
   A heavy footstep; a tramp.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Clamp \Clamp\, v. i.
   To tread heavily or clumsily; to clump.
   [1913 Webster]

         The policeman with clamping feet.        --Thackeray.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Clamp \Clamp\ (kl[a^]mp), n. [Cf. LG. & D. klamp, Dan. klampe,
   also D. klampen to fasten, clasp. Cf. Clamber, Cramp.]
   1. Something rigid that holds fast or binds things together;
      a piece of wood or metal, used to hold two or more pieces
      together.
      [1913 Webster]

   2.
      (a) An instrument with a screw or screws by which work is
          held in its place or two parts are temporarily held
          together.
      (b) (Joinery) A piece of wood placed across another, or
          inserted into another, to bind or strengthen.
          [1913 Webster]

   3. One of a pair of movable pieces of lead, or other soft
      material, to cover the jaws of a vise and enable it to
      grasp without bruising.
      [1913 Webster]

   4. (Shipbuilding) A thick plank on the inner part of a ship's
      side, used to sustain the ends of beams.
      [1913 Webster]

   5. A mass of bricks heaped up to be burned; or of ore for
      roasting, or of coal for coking.
      [1913 Webster]

   6. A mollusk. See Clam. [Obs.]
      [1913 Webster]

   Clamp nails, nails used to fasten on clamps in ships.
      [1913 Webster]

WordNet (r) 3.0 (2006):

clamp
    n 1: a device (generally used by carpenters) that holds things
         firmly together [syn: clamp, clinch]
    v 1: fasten or fix with a clamp; "clamp the chair together until
         the glue has hardened"
    2: impose or inflict forcefully; "The military government
       clamped a curfew onto the capital"

Moby Thesaurus II by Grady Ward, 1.0:

71 Moby Thesaurus words for "clamp":
   affix, alum, anchor, annex, astringent, attach, bear hug, belay,
   bite, brace, bracket, cement, cinch, clasp, clench, clinch, cling,
   clinging, clip, clutch, compress, compressor, constrictor,
   contractor, cramp, crush, death grip, embrace, engraft, ensphere,
   fasten, fastener, firm hold, fix, foothold, footing, graft,
   grapple, grasp, grip, gripe, hold, hug, iron grip, knit, make fast,
   moor, nip, pincer, pinch, press, purchase, put to, screw up,
   secure, seizure, set, set to, squeeze, styptic, styptic pencil,
   tenure, tight grip, tighten, toehold, trice up, trim, tweak, vice,
   vise, wad up