casern vs hostel

casern

noun
  • A lodging for soldiers in a garrison town (formerly usually near the rampart); a barracks. 

hostel

noun
  • A commercial overnight lodging place, with dormitory accommodation and shared facilities, especially a youth hostel. 

  • A temporary refuge for the homeless providing a bed and sometimes food. 

verb
  • To stay in a hostel during one's travels. 

  • To lodge (a person) in a hostel. 

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