arbor vs axletree

arbor

noun
  • A spindle of a wheel. 

  • A shady sitting place or pergola usually in a park or garden, surrounded by climbing shrubs, vines or other vegetation. 

  • A grove of trees. 

  • A bar for supporting cutting tools. 

  • An axis or shaft supporting a rotating part on a lathe. 

axletree

noun
  • A spindle or axle of a wheel. 

  • A stimulus or driving force. 

  • A bar or beam of wood or iron, connecting the opposite wheels of a carriage, on the ends of which the wheels revolve. 

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