concurrency vs correspondence

concurrency

noun
  • The property or an instance of being concurrent; something that happens at the same time as something else. 

  • A property of systems where several processes execute at the same time. 

  • A stretch of road that is shared between two or more numbered or named routes. 

correspondence

noun
  • A relation. 

  • Reciprocal exchange of civilities, especially conversation between persons by means of letters. 

  • Postal or other written communications. 

  • An agreement of situations or objects with an expected outcome. 

  • Newspaper or news stories. 

  • A similarity between physical and spiritual things (e.g. light to wisdom, or warmth to love) 

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