roadsweeper vs vacuum cleaner

roadsweeper

noun
  • A machine used to sweep streets 

  • A person employed to sweep streets 

vacuum cleaner

noun
  • A domestic or industrial mobile machine for cleaning floors and similar surfaces that draws dust and other particles into a container (a cyclonic type bin, or a filter bag) by the suction created by an electric motor driving a fan. 

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