balcony vs entresol

balcony

noun
  • An accessible structure overlooking a stage or the like. 

  • An accessible structure extending from a building, especially outside a window. 

entresol

noun
  • A mezzanine; an intermediate floor in a building, typically resembling a balcony; most often, the floor immediately above the ground floor and below a higher floor. 

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