Taxonomy of meanings for 何由:  

  • WHENCE
    • PPadVquestionfrom where
    • VPadVrhetorical questionwhence, from where in heaven? (presupposed answer: from nowhere)
  • WHY
    • VPadVwhy?
    • VPipostN{SUBJ}why is that
  • HOW
    • VPadVhow (on earth) CH