In architecture, an atrium is a large open-air or skylight-covered space surrounded by a building.
Atria were a common feature in Ancient Roman dwellings, providing light and ventilation to the interior. Modern atria, as developed in the late 19th and 20th centuries, are often several stories high, with a glazed roof or large windows, and often located immediately beyond a building's main entrance doors.
A late 19th-century artist's reimagining of an atrium in a Pompeian domus
Illustration of the atrium in the building of the baths in the Roman villa of "Els Munts", close to Tarraco
Victoria Hall in Halifax Town Hall, 1863
Cavaedium or atrium are Latin names for the principal room of an ancient Roman house, which usually had a central opening in the roof (compluvium) and a rainwater pool (impluvium) beneath it. The cavaedium passively collected, filtered, stored, and cooled rainwater. It also daylit, passively cooled and passively ventilated the house.
The well-preserved Tuscan atrium in the House of Menander, Pompeii. Note lararium in far corner by the stairs. Inwards-sloping roof supported by clear-span beams. View is through the tablinum, towards the front door.
The larger tetrastyle atrium of the Villa San Marco, Stabiae; four pillars support the roof. The central niche is the lararium; the two blocks of limestone (behind the pillar with the near-intact stucco) supported the arca, a strongbox or safe.
Tablelegs, puteal, and opus sectile impluvium, House of Publius Servilius Casca Longus (close-up)
The view over the impluvium, through the tablinum, and into the peristyle; the pillars, wallpaintings, and stonework were designed make this view impressive. House of Menander (view of the same room as the lead image of this article, but in the opposite direction).