/ Thesaurus / A Synonyms of atrial septal defect Find synonyms for: Noun1. atrial septal defect, septal defectusage: an abnormal opening between the left and right atria of the heartWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: labyrinth Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language