boulevard vs viaduct

boulevard

noun
  • A broad, well-paved and landscaped thoroughfare. 

  • A strip of land between a street and sidewalk. 

  • The landscaping on the sides of a boulevard or other thoroughfare. 

viaduct

noun
  • A bridge with several spans that carries road or rail traffic over a valley or other obstacles. 

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