ballpoint vs gladius

ballpoint

noun
  • A kind of needle with a rounded tip. 

  • A ballpoint pen. 

gladius

noun
  • A Roman sword roughly two feet long. 

  • A pen, a hard internal bodypart of certain cephalopods, made of chitin-like material. 

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