#boundary__edge__bound  a line determining the limits of an area
  supertype:  #line.shape  a length (straight or curved) without breadth or thickness; the trace of a moving point
  subtype:  #rim  the shape of a raised edge of a more or less circular object
  subtype:  #margin.boundary__border__perimeter  the boundary line or the area immediately inside the boundary
  subtype:  #periphery__fringe__outer_boundary__outerboundary  the outside boundary or surface of something
  subtype:  #brink.boundary__threshold__verge  a region marking a boundary
  subtype:  #upper_bound__upperbound  (mathematics) a number equal to or greater than any other number in a given set
     subtype:  #summit__crown__peak  the uppermost part of a shape; "at the peak of the pyramid"
  subtype:  #lower_bound__lowerbound  (mathematics) a number equal to or less than any other number in a given set
  subtype:  #thalweg.boundary  the middle of the chief navigable channel of a waterway that forms the boundary line between states

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