arris vs convexity

arris

noun
  • A sharp edge or ridge formed by the intersection of two curved surfaces 

  • A ridge formed on the surface of flaked stone, such as a arrowhead or hand axe, as the result of the intersection of two or more flake removals. 

  • A sharp edge or ridge formed by the intersection of two surfaces 

  • Buttocks, arse. 

convexity

noun
  • A convex line or surface. 

  • The state of being convex. 

  • A measure of the curvature in the relationship between the prices and yields of bonds. 

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