difficulty vs harmony

difficulty

noun
  • Physical danger from the environment, especially with risk of drowning 

  • An obstacle that hinders achievement of a goal. 

  • The state of being difficult, or hard to do. 

  • An objection. 

  • An awkward situation or quarrel. 

  • That which cannot be easily understood or believed. 

harmony

noun
  • A literary work which brings together or arranges systematically parallel passages of historians respecting the same events, and shows their agreement or consistency. 

  • A pleasing combination of elements, or arrangement of sounds. 

  • The relationship between two distinct musical pitches (musical pitches being frequencies of vibration which produce audible sound) played simultaneously. 

  • The academic study of chords. 

  • Agreement or accord. 

  • Two or more notes played simultaneously to produce a chord. 

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