(n) :
a square hall lighted from above, into which rooms open at one or more levels; a body cavity or chamber, especially an upper chamber of the heart that receives blood from the
veins and forces it into a
ventricle. An
auricle. In higher
vertebrates, the right atrium receives blood from the
superior vena cava and
inferior vena cava, and the left atrium receives blood from the left and right pulmonary veins