Source : Webster's Revised Unabridged Dictionary (1913)

Washboard \Wash"board`\, n.
   1. A fluted, or ribbed, board on which clothes are rubbed in
      washing them.

   2. A board running round, and serving as a facing for, the
      walls of a room, next to the floor; a mopboard.

   3. (Naut.) A broad, thin plank, fixed along the gunwale of
      boat to keep the sea from breaking inboard; also, a plank
      on the sill of a lower deck port, for the same purpose; --
      called also {wasteboard}. --Mar. Dict.

Source : WordNet®

washboard
     n 1: device consisting of a corrugated surface to scrub clothes
          on
     2: protective covering consisting of a broad plank along a
        gunwale to keep water from splashing over the side [syn: {splashboard}]