incision vs oblique mark

incision

noun
  • A cut, especially one made by a scalpel or similar medical tool in the context of surgical operation; the scar resulting from such a cut. 

  • A cut-back 

  • The act of cutting into a substance. 

oblique mark

noun
  • Synonym of slash ⟨/⟩, sometimes (generally proscribed) inclusive of similar marks such as the backslash ⟨\⟩. 

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