barbican vs buttress

barbican

noun
  • A temporary wooden tower built for defensive purposes. 

  • An opening in the wall of a fortress through which the guns are levelled; a narrow loophole through which arrows and other missiles may be shot. 

  • A tower at the entrance to a castle or fortified town 

  • A fortress at the end of a bridge. 

buttress

noun
  • A brick or stone structure built against another structure to support it. 

  • Anything that supports or strengthens. 

  • A buttress-root. 

  • Anything that serves to support something; a prop. 

  • A feature jutting prominently out from a mountain or rock. 

verb
  • To support something or someone by supplying evidence. 

  • To support something physically with, or as if with, a prop or buttress. 

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