roost vs superstructure

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 

superstructure

noun
  • All that part of a building above the basement. 

  • The sleepers and fastenings, in distinction from the roadbed. 

  • The social sphere of ideology which includes religion, art, politics, law and all traditional values. 

  • Any material structure or edifice built on something else; that which is raised on a foundation or basis. 

  • Any structure built above the top full deck (FM 55-501). 

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