boardwalk vs esplanade

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. 

esplanade

noun
  • Any clear, level space used for public walks or drives; especially, a terrace by the seaside. 

  • A clear space between a citadel and the nearest houses of the town. 

  • The glacis of the counterscarp, or the slope of the parapet of the covered way toward the country. 

  • A grass plat; a lawn. 

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