fencing vs guardrail

fencing

noun
  • Material used to make fences, fences used as barriers or an enclosure. 

  • Receiving and buying of stolen goods. 

  • The art or sport of duelling with swords, especially with the 17th- to 18th-century European dueling swords and the practice weapons descended from them (sport fencing). 

guardrail

noun
  • A rail set alongside a dangerous place as a barrier, to improve safety. 

  • Any barrier designed to prevent accidents or mistakes. 

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