atrium

American  

[ey-tree-uhm] / ˈeɪ tri əm /

noun

atria, plural atriums plural

1. Architecture.

   1. Also called cavaedium.  the main or central room of an ancient Roman house, open to the sky at the center and usually having a pool for the collection of rainwater.

   2. a courtyard, flanked or surrounded by porticoes, in front of an early or medieval Christian church.

   3. a skylit central court in a contemporary building or house.

2. Anatomy. either of the two upper chambers on each side of the heart that receive blood from the veins and in turn force it into the ventricles.

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atrium British  

/ ˈeɪtrɪəm, ˈɑː- /

noun

1. the open main court of a Roman house

2. a central often glass-roofed hall that extends through several storeys in a building, such as a shopping centre or hotel

3. a court in front of an early Christian or medieval church, esp one flanked by colonnades

4. anatomy a cavity or chamber in the body, esp the upper chamber of each half of the heart

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atrium Scientific  

/ ā′trē-əm /

atria plural

1. A chamber of the heart that receives blood from the veins and forces it by muscular contraction into a ventricle. Mammals, birds, reptiles, and amphibians have two atria; fish have one.

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Other Word Forms

Derived Forms

• atrial
  adjective
• interatrial
  adjective

Inflected Forms

Nouns

• atria
  plural
• atriums
  plural

Etymology

Origin of atrium

First recorded in 1570–80; from Latin (in anatomical sense, from New Latin )

Explanation

If you're in the atrium of a building, you're in a large central space, often one that's open and airy. You might arrange to meet a friend in the museum's atrium because of its central location and open feel. Often a key feature in a modern building, an atrium is usually spacious and several stories high with windows facing the sky. The atrium serves as a welcoming central area, with other rooms leading off of the space. An atrium can also refer to a chamber that's linked to other chambers or spaces. In your heart, the right atrium receives deoxygenated blood, while the left atrium receives oxygenated blood from the pulmonary vein.

Example Sentences

Bradford’s three-story map mural, “City of the Big Shoulders,” hangs on the west wall of the museum atrium.

From The Wall Street Journal • Jun. 16, 2026

The main atrium, or as I call it the “Hall of Mirrors,” is kind of compressed.

From Los Angeles Times • Apr. 13, 2026

On Holy Saturday, the Easter Vigil will be held in the atrium of St Peter's Basilica.

From Barron's • Apr. 1, 2026

In late 2023, Docter gathered Pixar’s staff in their steel and glass atrium to deliver an uncharacteristically blunt message.

From The Wall Street Journal • Mar. 7, 2026

The atrium is busy, lots of people arriving at their lunch hours to fill out forms and check on the status of their applications.

From "The Brightwood Code" by Monica Hesse

Related Words

• chamber
• entrance