washboard

I. Ord. Lang.: A board or slab with a ribbed surface for washing clothes on. They are made of wood, of corrugated zinc, earthenware, vulcanized rubber, . II. Technically : 2. Mining: An apparatus for washing ores. 3. Paper - making: A rag-engine (q. v.). 4. Plumb.: A bottom outlet in cisterns, . washer-hoop, s . A gasket between the flange and curb of a water-wheel.