dripstone vs hoodmould

dripstone

noun
  • A protective moulding over a door or window that allows rain to drip away from the structure. 

  • Stalactites and stalagmites collectively. 

  • A water filter in which impurities are removed by running water through a porous stone. 

hoodmould

noun
  • The outermost moulding which protrudes out of a wall over an archway (over the hood of a door, window or other opening), for decoration or the cover transitions between surfaces, and to discharge rain; a dripstone. 

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