Home›Browse›A›atriumatriumOur editors are putting together more complete content — check back in about 20 minutesatriumatrium — nounnoun1. a large open central area in a building, often with a glass roof1.nounDefinitiona large open central area in a building, often with a glass roofExampleThe hotel has a beautiful atrium with plants and a fountain.2. one of the two upper chambers of the heart2.nounDefinitionone of the two upper chambers of the heartExampleBlood flows from the atria into the ventricles.