three-ply vs trinity

three-ply

noun
  • Yarn having three strands 

adj
  • Having three strands or layers 

trinity

noun
  • A group or set of three people or things; three things combined into one. 

  • The state of being three; independence of three things; things divided into three. 

How often have the words three-ply and trinity occurred in a corpus of books? (source: Google Ngram Viewer )