noun, plural a·tri·a [ey-tree-uh] /ˈeɪ tri ə/, a·tri·ums.
- Also called .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 rain water.
- 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.
- 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.
noun plural atria (ˈeɪtrɪə, ˈɑː-)
- the open main court of a Roman house
- a central often glass-roofed hall that extends through several storeys in a building, such as a shopping centre or hotel
- a court in front of an early Christian or medieval church, esp one flanked by colonnades
- anatomy a cavity or chamber in the body, esp the upper chamber of each half of the heart
1570s, from Latin atrium “central court or main room of an ancient Roman house, room which contains the hearth,” sometimes said (on authority of Varro, “De Lingua Latina”) to be an Etruscan word, but perhaps from PIE *ater- “fire,” on notion of “place where smoke from the hearth escapes” (through a hole in the roof). Anatomical sense of “either of the upper cavities of the heart” first recorded 1870. Meaning “skylit central court in a public building” first attested 1967.
n. pl. a•tri•ums
- A chamber or cavity to which several chambers or passageways are connected.
- Either the right or the left upper chamber of the heart that receives blood from the veins and forces it into a ventricle.
- That part of the tympanic cavity that lies below the eardrum.
- A subdivision of the alveolar duct in the lung from which the alveolar sacs open.
Plural atria atriums
- 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.