caesura vs vertical bar

caesura

noun
  • The caesura mark ‖ or ||. 

  • Using two words to divide a metrical foot. 

  • A pause or interruption in a poem, music, building, or other work of art. 

  • A break of an era or other measure of history and time; where one era ends and another begins; turning point. 

vertical bar

noun
  • The symbol [[Unsupported titles/Vertical line#Translingual||]]. 

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