field hospital vs sickbay

field hospital

noun
  • A large mobile medical unit that temporarily takes care of casualties before they can be safely transported to more permanent hospital facilities. 

sickbay

noun
  • A room or area for the treatment of the sick or injured in a school. 

  • A place used as a hospital on board a ship, on a spaceship (in science fiction). 

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