discord vs tranquility

discord

verb
  • To untie things which are connected by a cord. 

noun
  • Any harsh noise, or confused mingling of sounds. 

  • Tension or strife resulting from a lack of agreement; dissension. 

  • An inharmonious combination of simultaneously sounded tones; a dissonance. 

  • Lack of concord, agreement or harmony. 

tranquility

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