arris vs hogback

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. 

hogback

noun
  • A sharp steep-sided ridge formed by the erosion of tilting strata 

  • A Viking grave marker taking the form of a recumbent monument, generally with a curved (hogbacked) ridge and outwardly curved sides. 

  • A hogframe. 

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