atrium

American  

[ey-tree-uhm] / ˈeɪ tri əm /

noun

plural

atria, atriums

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.

---

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

---

atrium Scientific  

/ ā′trē-əm /

plural

atria

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.

---

Other Word Forms

• atrial adjective
• interatrial adjective

Etymology

Origin of atrium

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

Example Sentences

Building codes have relaxed along with advances in fire-safety technology, making possible such a multi-story interior atrium.

From The Wall Street Journal • Mar. 20, 2026

At the centre of the main atrium stands an 83-tonne statue of Ramses II, the pharaoh who ruled Egypt for 66 years and presided over its golden age.

From Barron's • Nov. 1, 2025

Davis took this approach in the three-story atrium of his Calle del Sierra Residence in Stinson Beach, which is visually connected on all levels, showcasing exposed timber trusses and open lofts reachable via intricate ladders.

From Los Angeles Times • Aug. 6, 2025

Notable decor included a statue of a bride hanging onto a rope that dangled in an atrium, a wall of framed prosthetic eyeballs and leopard-print seating.

From Salon • Aug. 5, 2025

“Quick question,” I said as we hurried across the main atrium toward the library section.

From "Glitch" by Laura Martin

Related Words

• chamber
• entrance