#tractor  a wheeled vehicle with large wheels; used in farming and other applications
  supertype:  #wheeled_vehicle  a vehicle that moves on wheels and usually has a container for transporting things or people
  subtype:  #bulldozer__dozer  large powerful tractor; a large blade in front flattens areas of ground
     subtype:  #angledozer  a bulldozer with an angled moldboard to push earth to one side
  subtype:  #Caterpillar__cat  (trademark) a tractor that is driven by caterpillar tracks

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