Source : Webster's Revised Unabridged Dictionary (1913)

Plank \Plank\, v. t. [imp. & p. p. {Planked}; p. pr. & vb. n.
   {Planking}.]
   1. To cover or lay with planks; as, to plank a floor or a
      ship. ``Planked with pine.'' --Dryden.

   2. To lay down, as on a plank or table; to stake or pay cash;
      as, to plank money in a wager. [Colloq. U.S.]

   3. To harden, as hat bodies, by felting.

   4. (Wooden Manuf.) To splice together the ends of slivers of
      wool, for subsequent drawing.

   {Planked shad}, shad split open, fastened to a plank, and
      roasted before a wood fire.

Plank \Plank\, n. [OE. planke, OF. planque, planche, F. planche,
   fr. L. planca; cf. Gr. ?, ?, anything flat and broad. Cf.
   {Planch}.]
   1. A broad piece of sawed timber, differing from a board only
      in being thicker. See {Board}.

   2. Fig.: That which supports or upholds, as a board does a
      swimmer.

            His charity is a better plank than the faith of an
            intolerant and bitter-minded bigot.   --Southey.

   3. One of the separate articles in a declaration of the
      principles of a party or cause; as, a plank in the
      national platform. [Cant]

   {Plank road}, or {Plank way}, a road surface formed of
      planks. [U.S.]

   {To walk the plank}, to walk along a plank laid across the
      bulwark of a ship, until one overbalances it and falls
      into the sea; -- a method of disposing of captives
      practiced by pirates.

Source : WordNet®

plank
     n 1: a stout length of sawn timber; made in a wide variety of
          sizes and used for many purposes [syn: {board}]
     2: an endorsed policy in the platform of a political party

plank
     v 1: cover with planks; "The streets were planked" [syn: {plank
          over}]
     2: set (something or oneself) down with or as if with a noise;
        "He planked the money on the table"; "He planked himself
        into the sofa" [syn: {flump}, {plonk}, {plop}, {plunk}, {plump
        down}, {plunk down}, {plump}]
     3: cook and serve on a plank; "Planked vegetable"; "Planked
        shad"