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.
1) n. rippling effect on graded, hardpack roads caused by slow moving, poorly suspended vehicles disrupting the road surface with wheel hop. 2) v. To create a washboard surface on a road by driving slower than conditions allow.
A washboard is a tool designed for hand washing clothing. With mechanized cleaning of clothing becoming more common by the end of the 20th century, the washboard has become better known for its originally subsidiary use as a musical instrument.