Leavenworth vs stockade

Leavenworth

name
  • A surname. 

  • A city, the county seat of Leavenworth County, Kansas. 

  • A town in Indiana; named for founders Zebulon and Seth Leavenworth. 

  • A city in Washington. 

  • An unincorporated community in Minnesota; named for American soldier Henry Leavenworth. 

stockade

verb
  • To enclose in a stockade. 

noun
  • a military prison 

  • an enclosure protected by a wall of wooden posts 

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