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a·tri·um

(ātrē-əm)

n. pl. a·tri·a (ātrē-ə) or a·tri·ums

1. Architecture A rectangular court, as:

a. A usually skylit central area, often containing plants, in some modern buildings, especially of a public or commercial nature.

b. The open area in the center of an ancient Roman house.

c. The forecourt of a building, such as an early Christian church, enclosed on three or four sides with porticoes.

2. Anatomy A body cavity or chamber, especially either of the upper chambers of the heart that receives blood from the veins and forces it into a ventricle. Also called auricle.

[Latin ātrium; see āter- in the Appendix of Indo-European roots.]

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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