[ ey-tree-uhm ]
See synonyms for atrium on
noun,plural a·tri·a [ey-tree-uh], /ˈeɪ tri ə/, a·tri·ums.
  1. Architecture.

    • 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.

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

    • 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.

Origin of atrium

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

Other words from atrium

  • a·tri·al, adjective
  • in·ter·a·tri·al, adjective

Words Nearby atrium Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use atrium in a sentence

British Dictionary definitions for atrium


/ (ˈeɪtrɪəm, ˈɑː-) /

nounplural atria (ˈeɪtrɪə, ˈɑː-)
  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

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

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

Origin of atrium

C17: from Latin; related to āter black, perhaps originally referring to the part of the house that was blackened by smoke from the hearth

Derived forms of atrium

  • atrial, adjective

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for atrium


[ ātrē-əm ]

Plural atria atriums
  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.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.