aortic septal defect

n.
  1. A small congenital opening between the aorta and pulmonary artery just above the semilunar valves.aorticopulmonary septal defect
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.