blur vs gradation

blur

noun
  • Something that appears hazy or indistinct 

  • A smear, smudge or blot 

adj
  • In a state of doubt or confusion. 

verb
  • To cause imperfection of vision in; to dim; to darken. 

  • To become indistinct. 

  • To transfer the input focus away from. 

  • To smear, stain or smudge. 

  • To make indistinct or hazy, to obscure or dim. 

gradation

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

  • A calibration marking. 

  • 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. 

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

  • The act of gradating or arranging in grades. 

verb
  • To form with gradations. 

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