quadrangle vs stockade

quadrangle

noun
  • The buildings forming the border of such a courtyard. 

  • A geometric shape with four angles and four straight sides; a four-sided polygon. 

  • A courtyard which is quadrangular. 

stockade

noun
  • an enclosure protected by a wall of wooden posts 

  • a military prison 

verb
  • To enclose in a stockade. 

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