Definify.com
Webster 1913 Edition
Washboard
Wash′boardˊ
,Noun.
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.