incurvation vs rounding

incurvation

noun
  • A curving inwards; the condition of being curved inwards. 

  • The act of acquiring or being given a curved form; an instance of curving or bending. 

  • The state of being curved or bent; any curved shape or formation; curvature; a curve; a bend. 

rounding

noun
  • A rounded surface; a curve. 

  • The numerical value obtained by this process. 

  • The act by which a numerical value is rounded. 

  • In bookbinding, the shaping of the folded and sewed sheets into a convex form at the back. 

  • The act of making anything round, as the lips in pronouncing some vowels. 

adj
  • Round or nearly round; becoming round; roundish. 

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