gradation vs notch

gradation

noun
  • Any degree or relative position in an order or series. 

  • A calibration marking. 

  • A passing by small degrees from one tone or shade, as of color, to another. 

  • A diatonic succession of chords. 

  • Apophony. 

  • A gradual change within one parameter, or an overlapping of two blocks of sound. 

  • A sequence of gradual, successive stages; a systematic progression. 

  • The act of gradating or arranging in grades. 

verb
  • To form with gradations. 

notch

noun
  • A level or degree. 

  • An indentation. 

  • A mountain pass; a defile. 

  • A discontinuous change in a taxation schedule. 

  • Woman. 

  • Such a cut, used for keeping a record. 

  • A portion of a mobile phone that overlaps the edge of the screen, used to house camera, sensors etc. while maximizing screen space. 

verb
  • To cut a notch in (something). 

  • To achieve (something); to add to one's score or record of successes. 

  • To join by means of notches. 

  • To record (a score or similar) by making notches on something. 

  • To fit (an arrow) to a bow by means of the notch cut at the end of the arrow; to nock. 

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