billy vs life preserver

billy

noun
  • A slubbing or roving machine. 

  • A good friend. 

  • A billy club. 

  • A billy goat. 

  • A male goat; a ram. 

  • A bong for smoking marijuana. 

  • A tin with a swing handle used to boil tea over an open fire; a billycan; a billypot. 

  • A condom. 

life preserver

noun
  • A buoyant ring or vest intended to keep a person afloat. 

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