bawn vs greensward

bawn

noun
  • A defensive wall built around a tower house. It was once used to protect livestock during an attack. 

  • A cattle-fort; a building used to shelter cattle. 

greensward

noun
  • A tract of land that is green with grass. 

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