atri·um 
/ˈeɪtrijəm/ noun
plural atria /ˈeɪtrijəm/ noun /ˈeɪtrijə/ also atriums [count] 1 : an open area inside a tall building that has windows to let light in from above 2 technical : one of two sections of the heart that take in blood from the veins — compare ventricle
