inflection vs tonus

inflection

noun
  • A change in pitch or tone of voice. 

  • Change in the form of a word (morphologic change) to express different grammatical categories. 

  • Diffraction. 

  • Any form produced by such an instance of a change, such as the principal parts for any given stem: any of the declined or conjugated forms that constitute its declension or conjugation. 

  • An affix representing such an instance. 

  • A turning away from a straight course. 

  • A change in curvature from concave to convex or from convex to concave. 

  • An instance of such change. 

tonus

noun
  • tonicity; tone 

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