From Longman Dictionary of Contemporary Englishwashboardwash‧board /ˈwɒʃbɔːd $ ˈwɒːʃbɔːrd, ˈwɑːʃ-/ noun [countable] 1 DHCa piece of metal with a slightly rough surface, used in the past for rubbing clothes on when washing them2 → washboard stomach
Examples from the Corpus
washboard• Respect for the past does not mean a reliance on fiddle and washboard.• He was massive, monumental, lacking only the ideal washboard stomach.• Henry stayed up quite late and Fred gave him a lesson on his old washboard.• They boiled laundry in tubs, scrubbed it on washboards until knuckles were raw, and wrung it out by hand.• If Miss Bingham's idea for the band came to anything Henry just might ask him about playing that washboard with thimbles.• A fork and a couple of shining spoons lay beside it, along with the washboard and scrubbing brush.• Stove-blacking, coal-scuttle filling and vigorous work with the washboard were definitely out. 