roost vs skillion

roost

noun
  • The inner roof of a cottage. 

  • A group of birds roosting together. 

  • A tidal race. 

  • A bedroom 

  • The place where a bird sleeps (usually its nest or a branch). 

verb
  • to spend the night 

  • To settle on a perch in order to sleep or rest 

skillion

noun
  • A room built against the back of another building, having a separate roof. 

  • Any indefinitely large number. 

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