mezzanine vs penthouse

mezzanine

noun
  • An apartment, room, etc., on such an intermediate floor. 

  • An intermediate floor or storey in between the main floors of a building; specifically, one that is directly above the ground floor which does not extend over the whole floorspace of the building, and so resembles a large balcony overlooking the ground floor; an entresol. 

  • The lowest balcony in an auditorium, cinema, theatre, etc.; the dress circle. 

adj
  • Characteristic of or relating to high-interest loans which have no collateral, and are regarded as intermediate in nature, ranking above equity but below secured loans. 

  • Fulfilling an intermediate or secondary function. 

verb
  • To fit (a building or other place) with a mezzanine floor. 

penthouse

noun
  • An apartment or suite found on an upper floor, or floors, of a tall building, especially one that is expensive or luxurious with panoramic views. Sometimes these are located just under "penthouse mechanical" floors. 

  • Any of the sloping roofs at the side of a real tennis court. 

  • An outhouse or other structure (especially one with a sloping roof) attached to the outside wall of a building, sometimes as protection from the weather. 

verb
  • To provide with a penthouse, shelter by means of a shed sloping from a wall, or anything similar. 

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