a central hall or court in a modern building, with rooms or galleries opening off it, often glass-covered.
plans call for a new atrium to be built behind the facade
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Anatomy
each of the two upper cavities of the heart from which blood is passed to the ventricles. The right atrium receives deoxygenated blood from the veins of the body; the left atrium receives oxygenated blood from the pulmonary vein.
