#narrowing.contour  an instance of becoming narrow
  supertype:  contour__shape__form__configuration  any spatial attribute (especially as defined by outline); "he could barely make out their shapes through the smoke"
  subtype:  coarctation  (biology) a congenital narrowing of the aorta
  subtype:  taper  the property possessed by a shape that narrows toward a point (as a wedge or cone)
     subtype:  pointedness__pointednes  the property of a shape that tapers to a sharp point
     subtype:  unpointedness__unpointednes  the property of having only a dull point if any
  subtype:  bottleneck__constriction  a narrowing that reduces the flow through a channel

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