gazebo vs rotunda

gazebo

noun
  • A belvedere, either a type of summer-house or a roofed, detached porch-like structure, usually in a yard, park or lawn. 

rotunda

noun
  • A round building, usually small, often with a dome. 

  • A Gothic typeface used in early printed books in Northern Italy, based on a rounded script developed in the 13th cent.; the manuscript hand on which this typeface was based. 

  • A roundabout; a road junction at which traffic streams circularly around a central island. 

  • A form of cupola that has pentagons rather than squares or rectangles. 

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