plexus vs tracery

plexus

noun
  • An interwoven combination of parts or elements in a structure or system. 

  • The system of equations required for the complete expression of the relations which exist between a set of quantities. 

  • A network of anastomosing or interwoven nerves, blood vessels, or lymphatic vessels. 

tracery

noun
  • A delicate interlacing of lines reminiscent of the architectural ornament. 

  • Bars or ribs, usually of stone or wood, or other material, that subdivide an opening or stand in relief against a door or wall as an ornamental feature. 

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