excavator vs minesweeper

excavator

noun
  • A vehicle, often on tracks, used to dig ditches etc. 

  • A person who excavates. 

  • A curette used to scrape out pathological material. 

minesweeper

noun
  • A vehicle, device or person with the purpose of removing explosive mines (landmines or water mines). 

  • A logic-based computer game in which the player has to discover the position of mines in a rectangular grid, based on numerical hints. 

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