advocate vs public address system

advocate

noun
  • A person who supports others to make their voices heard, or ideally for them to speak up for themselves. 

  • A person who speaks in support of something, or someone. 

  • Someone whose job is to speak for someone's case in a court of law; a counsel. 

  • Anyone who argues the case of another; an intercessor. 

verb
  • To appeal from an inferior court to the Court of Session. 

  • To engage in advocacy. 

  • To call a case before itself for decision. 

  • To encourage support for something. 

  • To plead in favour of; to defend by argument, before a tribunal or the public; to support, vindicate, or recommend publicly. 

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 advocate and public address system occurred in a corpus of books? (source: Google Ngram Viewer )