airlock vs foyer

airlock

noun
  • A vestibule, foyer or entranceway with doors to the exterior on one end and doors to the interior on the other, functioning to keep indoor and outdoor air, humidity, and air temperatures separate. 

  • A sealed, airtight chamber, such as in a manned spacecraft or submarine, used to provide access to and from the sealed area without allowing air out or water in. 

foyer

noun
  • A lobby, corridor, or waiting room, used in a hotel, theater, etc. 

  • A hostel offering accommodation and work opportunities to homeless young people. 

  • The crucible or basin in a furnace which receives the molten metal. 

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