plank vs sprag

plank

noun
  • A long, broad and thick piece of timber, as opposed to a board which is less thick. 

  • Physical exercise in which one holds a pushup position for a measured length of time. 

  • A stupid person, idiot. 

  • That which supports or upholds. 

  • A political issue that is of concern to a faction or a party of the people and the political position that is taken on that issue. 

verb
  • To cover something with planking. 

  • To pose for a photograph while lying rigid, face down, arms at side, in an unusual place. 

  • To lay down, as on a plank or table; to stake or pay cash. 

  • To harden, as hat bodies, by felting. 

  • To bake (fish, etc.) on a piece of cedar lumber. 

  • To splice together the ends of slivers of wool, for subsequent drawing. 

sprag

noun
  • A billet of wood; a piece of timber, a similar solid object or constructed unit used as a prop. 

  • A young salmon. 

verb
  • To prop or sustain with a sprag. 

  • To check the motion of, as a carriage on a steep slope, by putting a sprag between the spokes of the wheel. 

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