The Collaborative International Dictionary of English v.0.48:

Calk \Calk\ (k[a^]lk), v. t. [E.calquer to trace, It. caicare to
   trace, to trample, fr. L. calcare to trample, fr. calx heel.
   Cf. Calcarate.]
   To copy, as a drawing, by rubbing the back of it with red or
   black chalk, and then passing a blunt style or needle over
   the lines, so as to leave a tracing on the paper or other
   thing against which it is laid or held. [Written also
   calque]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Calk \Calk\ (k[add]k), n. [Cf. AS. calc shoe, hoof, L. calx,
   calcis, heel, calcar, spur.]
   1. A sharp-pointed piece of iron or steel projecting downward
      on the shoe of a horse or an ox, to prevent the animal
      from slipping; -- called also calker, calkin.
      [1913 Webster]

   2. An instrument with sharp points, worn on the sole of a
      shoe or boot, to prevent slipping.
      [1913 Webster]

   3. same as caulk[2], n..
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Calk \Calk\ (k[add]k), v. i.
   1. To furnish with calks, to prevent slipping on ice; as, to
      calk the shoes of a horse or an ox.
      [1913 Webster]

   2. To wound with a calk; as when a horse injures a leg or a
      foot with a calk on one of the other feet.
      [1913 Webster]

   3. same as caulk[2], v. t..
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Calk \Calk\ (k[add]k), v. t. [imp. & p. p. Calked; p. pr. &
   vb. n. Calking.] [Either corrupted fr. F. calfater (cf. Pg.
   calafetar, Sp. calafetear), fr. Ar. qalafa to fill up
   crevices with the fibers of palm tree or moss; or fr. OE.
   cauken to tred, through the French fr. L. calcare, fr. calx
   heel. Cf. Calk to copy, Inculcate.]
   1. To drive tarred oakum into the seams between the planks of
      (a ship, boat, etc.), to prevent leaking. The calking is
      completed by smearing the seams with melted pitch.
      [1913 Webster]

   2. To make an indentation in the edge of a metal plate, as
      along a seam in a steam boiler or an iron ship, to force
      the edge of the upper plate hard against the lower and so
      fill the crevice.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Caulk \Caulk\, n.
   1. See Calk.
      [1913 Webster]

   2. a viscous semisolid material of varying composition used
      to fill in seams of objects which are exposed to water,
      such as wooden ships or bath tiles; -- called also calk
      and caulking. After applying in a semisolid form, the
      material hardens and dries to form a waterproof seal. It
      is used in the process of caulking. It is sometimes
      applied together with a rope-like cord to fill larger
      seams.
      [PJC]

WordNet (r) 3.0 (2006):

calk
    n 1: a metal cleat on the bottom front of a horseshoe to prevent
         slipping [syn: calk, calkin]
    v 1: provide with calks; "calk horse shoes"
    2: seal with caulking; "caulk the window" [syn: caulk, calk]
    3: injure with a calk