threefold vs triplex

threefold

verb
  • To make threefold; to triple. 

noun
  • An algebraic variety of dimension 3. 

adv
  • by a factor of three 

adj
  • triple 

  • three times as great 

triplex

verb
  • To make triplex. 

noun
  • A building with three apartments or divisions. 

  • A dwelling unit with three floors. 

  • Triple time. 

  • A throwing motion where three balls are thrown with one hand at the same time. 

adj
  • Having three units, divisions, suites, apartments 

  • Having three floors 

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