Definition from Wiktionary, the free dictionary
washboard (plural washboards)
- a board with a corrugated surface against which laundry may be rubbed
- (music) such a board used as a simple percussion instrument
- (nautical) a board fastened along a ship's gunwale to prevent splashing; a splashboard
- A stretch of ripples or bumps on a dirt or gravel road, mostly occurring at corners; which is caused by wear from traffic, erosion from wet weather, or poor grading.
board to do laundry
a board on the gunwale of a boat to stop splashing - a splash board