ruler vs straightedge

ruler

noun
  • A (usually rigid), flat, rectangular measuring or drawing device with graduations in units of measurement; a straightedge with markings. 

  • A person who rules or governs; someone or something that exercises dominion or controlling power over others. 

verb
  • To beat with a ruler (as a traditional school punishment). 

straightedge

noun
  • A flat, rectangular tool used to draw, cut or check the straightness of straight lines. 

adj
  • Living one's life opposing or eschewing the use of substances such as alcohol, tobacco, and drugs. 

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