from
The Collaborative International Dictionary of English v.0.48
Washboard \Wash"board`\, n.
1. A fluted, or ribbed, board on which clothes are rubbed in
washing them.
[1913 Webster]
2. A board running round, and serving as a facing for, the
walls of a room, next to the floor; a mopboard.
[1913 Webster]
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.
[1913 Webster]