gable vs sprocket

gable

noun
  • The triangular area at the peak of an external wall adjacent to, and terminating, two sloped roof surfaces (pitches). 

sprocket

noun
  • A flared extension at the base of a sloped roof. 

  • A toothed wheel that enmeshes with a chain or other perforated band. 

  • The tooth of such a wheel. 

  • A placeholder name for an unnamed, unspecified, or hypothetical manufactured good or product. 

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