brig vs glasshouse

brig

noun
  • A jail or guardhouse, especially in a naval military prison or jail on a ship, navy base, or (in fiction) spacecraft. 

  • A two-masted vessel, square-rigged on both foremast and mainmast 

  • Bridge. 

  • Brigadier. 

glasshouse

noun
  • A military prison. 

  • A greenhouse, especially one for commercial use. 

  • A building where glass or glassware is manufactured. 

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