enigma vs known

enigma

noun
  • A species of grasshopper, Oedaleonotus enigma. 

  • A riddle, or a difficult problem. 

  • Mysteriousness; obscurity; lack of clarity. 

  • The Talaud kingfisher, Todiramphus enigma. 

  • A rare species of moth, Heliothis enigma. 

  • A style of literature characterized by obscurity and hints of transcendental meaning. 

  • Something or someone puzzling, mysterious or inexplicable. 

  • A protein with three LIM domains (a conserved cysteine- and histidine-rich structure of two adjacent zinc fingers) at the C terminus that regulates protein phosphorylation. 

  • Riddles and puzzles, collectively. 

known

noun
  • Any fact or situation which is known or familiar. 

  • A constant or variable the value of which is already determined. 

adj
  • Accepted, familiar, researched. 

  • Identified as a specific type; famous, renowned. 

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