boardwalk vs sidewalk

boardwalk

noun
  • A slightly elevated path for pedestrians over sandy or swampy ground, typically made out of wood; specifically (Canada, US) one running alongside a body of water or beach. 

verb
  • To install a boardwalk over. 

sidewalk

noun
  • (usually) a paved footpath located at the side of a road, for the use of pedestrians 

  • any paved footpath, even if not located at the side of a road 

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