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

See Examples For:

atrium atria atriums

The mitral valve sits between the heart's left atrium and left ventricle.

From Science Daily ● Jul. 12, 2026

The left atrium receives oxygen rich blood returning from the lungs, while the left ventricle pumps that blood throughout the body.

From Science Daily ● Jul. 12, 2026

They can also lead by example—for instance, by holding a team meeting in the atrium everyone walks past but never enters.

From The Wall Street Journal ● Jun. 14, 2026

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

From Los Angeles Times ● Apr. 13, 2026

We were crossing the atrium that led to the parking lot.

From "Burning Blue" by Paul Griffin

La Gerche’s team, which also includes Elliott, will track whether there’s rubbing of the atria against the spine that leads to inflammation and later AF.

From Science Magazine ● May 14, 2024

In AF, the upper chambers of the heart, called the atria, beat erratically and at runaway speeds, out of sync with the lower chambers.

From Science Magazine ● May 14, 2024

The right ventricle is one of the heart's four chambers, along with the left ventricle and the left and right atria.

From Science Daily ● Dec. 8, 2023

Premature atrial contractions are a type of irregular heartbeat that emanates from the top chambers of the heart, called the atria, while premature ventricular contractions come from the bottom chambers, called the ventricles.

From Washington Post ● Mar. 22, 2023

My arms are atria and my legs are ventricles and I pump the blood all around the right way because there has to be something I can do.

From "Mockingbird" by Kathryn Erskine

But its soaring atriums decorated with onyx and green marble could hardly be better calculated to induce jealousy in Trump, who frequently raves about the opulent dwellings of other foreign leaders.

From Barron's ● Jul. 7, 2026

This is an attraction, from the queue to its ending, of constant reveals — tunnels give way to gorgeous atriums, and each set piece aims to be larger, more lively than the last.

From Los Angeles Times ● Apr. 9, 2025

Inside the building, mezzanines give way to atriums.

From Seattle Times ● Jan. 23, 2023

But away from the structure’s great atriums, life for the ordinary denizens of South London was often less refined.

From Washington Post ● Mar. 4, 2021

This temple was huge, a maze of chambers and halls and atriums.

From "Beasts of Prey" by Ayana Gray

Related Words

• chamber
• entrance