externals vs facade

externals

facade

noun
  • A deceptive or insincere outward appearance. 

  • An object serving as a simplified interface to a larger body of code, as in the facade pattern. 

  • The face or front (most visible side) of any other thing, such as an organ. 

  • The face of a building, especially the front view or elevation. 

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