concordance vs level set

concordance

noun
  • Agreement; accordance; consonance. 

  • A list of occurrences of a word or phrase from a corpus, with the immediate context. 

  • An alphabetical verbal index showing the places in the text of a book where each principal word may be found, with its immediate context in each place. 

level set

noun
  • A state of mutual understanding among parties 

  • An event consisting of level setting 

  • The set of values x for which a real-valued function f(x) is equal to a given constant. 

verb
  • To establish a baseline of mutual understanding 

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