hoover vs street sweeper

hoover

noun
  • A vacuum cleaner, irrespective of brand. 

verb
  • To clean (a room, etc.) with a vacuum cleaner, irrespective of brand. 

  • To use a vacuum cleaner, irrespective of brand. 

  • To suck in or inhale, as if by a vacuum cleaner. 

street sweeper

noun
  • A machine used to sweep streets. 

  • A person who is employed to sweep streets, pavements, and gutters, keeping them clear of litter. 

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