atriumcommon nounSyllable DecompositionatriumEtymologyexpandfrom Latin atrium.Definitions1. Part of an ancient Roman house consisting of an inner courtyard, often surrounded by a covered gallery supported by two rows of columns, which is called a portico.architectureexpand2. Covered or uncovered inner courtyard or room with overhead lighting.by extensionexpand3. Atrium in the new nomenclature; each of the two cavities of the heart that are located above the two ventricles.anatexpandSynonymspatiocouroreillettePluralatriumsAnagrammuraitTranslationsenglish:atriumspanish:atriofinnish:valopihaitalian:atrioSee alsoatrial (adj.)