balustrade vs barbed wire

balustrade

noun
  • A row of balusters topped by a rail, serving as an open parapet, as along the edge of a balcony, terrace, bridge, staircase, or the eaves of a building. 

barbed wire

noun
  • Twisted strands of steel wire, often coated with zinc, having barbs evenly spaced along them; used to construct agricultural and military fences. 

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