gatepost vs parapet

gatepost

noun
  • a vertical post from which a gate is hung/attached. 

parapet

noun
  • Part of a perimeter that extends above the roof. 

  • A fortification consisting of a wall. 

  • A low protective wall. 

  • Hyponym: balustrade 

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