Definitions for Atriumˈeɪ tri əm; ˈeɪ tri ə
Random House Webster's College Dictionary
a•tri•umˈeɪ tri əm; ˈeɪ tri ə(n.)(pl.)a•tri•a; a•tri•ums.
a usu. skylighted lobby or court, often several stories high, in an office building, hotel, etc. a central courtyard or patio open to the sky. the main or central room of an ancient Roman house, open to the sky at the center. a courtyard, flanked or surrounded by porticoes, in front of an early or medieval Christian church.
a cavity of the body. either of the two thin-walled upper chambers of the heart that receive blood from the veins and force it into the ventricles.
Ref: Also called auricle.
Origin of atrium:
1570–80; < NL, L
any chamber that is connected to other chambers or passageways (especially one of the two upper chambers of the heart)
the central area in a building; open to the sky
A central room or space in ancient Roman homes, open to the sky in the middle; a similar space in other buildings.
A square hall lit by daylight from above, into which rooms open at one or more levels.
Any enclosed body cavity or chamber
An upper chamber of the heart that receives blood from the veins and forces it into a ventricle. 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.
A microscopic air sac within a pulmonary alveolus.
A cavity inside a porate aperture of a pollen grain formed by the separation of the sexine and nexine layers, widening toward the interior of the grain.
Origin: From ātrium (entry hall)
a square hall lighted from above, into which rooms open at one or more levels
an open court with a porch or gallery around three or more sides; especially at the entrance of a basilica or other church. The name was extended in the Middle Ages to the open churchyard or cemetery
the main part of either auricle of the heart as distinct from the auricular appendix. Also, the whole articular portion of the heart
a cavity in ascidians into which the intestine and generative ducts open, and which also receives the water from the gills. See Ascidioidea