piazza vs stoa

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). 

stoa

noun
  • In Ancient Greece, a walkway with a roof supported by colonnades, often with a wall on one side; specifically, the Great Hall in Athens. 

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