n. (pl. atriums or atria) 1 a the central court of an ancient Roman house. b a usu. skylit central court rising through several storeys with galleries and rooms opening off at each level. c esp. US (in a modern house) a central hall or glazed court with rooms opening off it. 2 Anat. a cavity in the body, esp. one of the two upper cavities of the heart, receiving blood from the veins. atrial adj.
[ L ]