diagnosis vs unison

diagnosis

verb
  • Synonym of diagnose 

noun
  • The identification of the nature and cause of something (of any nature). 

  • A written description of a species or other taxon serving to distinguish that species from all others; especially a description written and published in Latin. 

  • The identification of the nature and cause of an illness. 

unison

noun
  • A sound or note having the same pitch as another, especially when used as the base note for an interval; a unison string. 

  • The state of being in harmony or agreement; harmonious agreement or togetherness, synchronisation. 

  • Identical pitch between two notes or sounds; the simultaneous playing of notes of identical pitch (or separated by one or more octaves). 

  • Two or more voices speaking the same words together. 

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