promoter vs public address system

promoter

noun
  • One who promotes entertainment events or goods. 

  • The section of DNA that controls the initiation of RNA transcription as a product of a gene. 

  • An accelerator of catalysis that is not itself a catalyst. 

  • One who promotes. 

public address system

noun
  • An electronic voice-amplification apparatus, usually containing a set of two loudspeakers and a central control unit, used for singing, giving a speech, play-by-play commentary at events, or broadcasting in public areas like in airports or stations. 

How often have the words promoter and public address system occurred in a corpus of books? (source: Google Ngram Viewer )