esplanade vs prom

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. 

prom

noun
  • A promenade. 

  • A formal ball held at a high school or college on special occasions; e.g,. near the end of the academic year. 

  • A promenade concert. 

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