highway vs viaduct

highway

noun
  • A road that is higher than the surrounding land and has drainage ditches at the sides 

  • A way; a path that leads to a certain destiny 

  • A main public road, especially a multi-lane, high-speed thoroughfare. 

  • Any public road for vehicular traffic. 

  • Synonym of bus (“common connection for two or more circuits or components”) 

verb
  • To travel on a highway 

viaduct

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

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