freeboard vs washboard

freeboard

noun
  • The vertical distance between the waterline and the uppermost watertight deck of a vessel. 

  • The distance between a water level and the top of something that contains or restrains it (such as a dam). 

  • The distance between the top of sea ice and the water level. 

  • A type of skateboard which simulates the movement of a snowboard when used on a downhill coarse, allowing snowboarding techniques, which has an addition of two centerline casters that extend below the traditional skateboard wheels and bogies. 

washboard

noun
  • 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 caused by interaction between traffic and road surface. 

  • Such a board used as a simple percussion instrument. 

  • A board with a corrugated surface against which laundry may be rubbed. 

verb
  • To play a washboard. 

  • To move up and down or back and forth across the surface of a hive, possibly to lay down a layer of propolis and wax. 

  • To produce a rippled texture on a surface. 

How often have the words freeboard and washboard occurred in a corpus of books? (source: Google Ngram Viewer )