attic vs dripstone

attic

noun
  • The space, often unfinished and with sloped walls, directly below the roof in the uppermost part of a house or other building, generally used for storage or habitation. 

  • A person's head or brain. 

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. 

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