agora vs piazza

agora

noun
  • A marketplace, especially in Classical Greece. 

  • Since 1960, a monetary unit and coin of Israel, the 100th part of a shekel / sheqel. 

  • A place for gathering. 

piazza

noun
  • A public square, especially in Italian cities. 

  • A roofed gallery or arcade (for example around a public square or in front of a building). 

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