washboard

noun

1. a rectangular board or frame, typically with a corrugated metallic surface, on which clothes are rubbed in the process of washing.
2. a baseboard around the walls of a room.
3. Also called splashboard. Nautical.
   1. a thin, broad plank fastened to and projecting above the gunwale or side of a boat to keep out the spray and sea.
   2. a similar board on the sill of a port.