broker vs middleperson

broker

noun
  • A mediator between a buyer and seller. 

  • An agent involved in the exchange of messages or transactions. 

  • A stockbroker. 

  • A mediator in general, one who liaises between two or more parties to attempt to achieve an outcome of some kind. 

verb
  • To act as a broker; to mediate in a sale or transaction. 

  • To act as a broker in; to arrange or negotiate. 

middleperson

noun
  • An intermediate dealer of any gender; a middleman or middlewoman. 

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