What Is an Oriel Window?

Look for the Bracket on the Bottom

Victorian Row Houses with Oriel Bay Windows
Victorian Row Houses with Oriel Bay Windows. Photo by David Wasserman/Stockbyte/Getty Images (cropped)

An oriel window is a set of windows, arranged together in a bay that protrudes from the face of a building on an upper floor and braced underneath by a bracket or corbel. Most people call them bay windows when located on the first floor and oriel windows only if they are on an upper floor.

This type of bay window probably originated during the Middle Ages, in both Europe and the Middle East. The oriel window may have developed from a form of porch—oriolum is the Medieval Latin word for porch or gallery.

In Islamic architecture, the mashrabiya (also called moucharabieh and musharabie) is considered a type of oriel window. Known for its decorative lattice, the mashrabiya traditionally was a protruding box-like architectural detail that functioned as a way to keep drinking water cool and to ventilate interior spaces in a hot Arabian climate. The mashrabiya continues to be a common feature of modern Arab architecture.

In Western architecture these protruding windows most certainly attempted to catch the movement of the sun, especially during winter months when daylight is limited. Capturing light and bringing fresh air into Medieval architecture was thought to benefit health, both physically and mentally. Bay windows also expand the interior living space without changing the footprint of a building—a centuries-old trick when property taxes are calculated on a foundation's width and length.

Oriel windows are not dormers, because they do not break the line of the roof.

However, some architects such as Paul Williams (1894-1980) have used both oriel and dormer windows on one house to create an interesting and complementary effect.

Characteristics of the Oriel Window:

Defining features of an oriel window include:

  • Projects from the wall
  • Does not extend to the ground
  • Supported by brackets or corbels, often very ornate, symbolic, and ornamental in Medieval times
  • Often on upper floors

Oriel Windows in American Architectural Periods:

The reign of British Queen Victoria, between 1837 and 1901, was a long era of growth and expansion in both Great Britain and the United States. Many architectural styles are associated with this time period, and particular styles of American Victorian architecture are characterized by having oriel windows. Buildings in the Gothic Revival and Tudor styles often have oriel windows. Eastlake Victorian, Chateauesque, and Queen Anne styles may combine oriel-like windows with turrets, which are characteristic of those styles. Many urban brownstone facades in the Richardsonian Romanesque style have oriel windows.

In American skyscraper history, the Chicago School architects are known to have experimented with oriel designs. Most notably, John Wellborn Root's spiral staircase for the 1888 Rookery Building in Chicago is known as the oriel staircase. Root's design is actually a fire escape required by the city after the Great Chicago Fire of 1871. Root enclosed the stairs in what architecturally appeared to be a very long oriel window attached to the rear of the building. Like a typical oriel window, the staircase did not reach the ground floor, but ended on the second floor, now part of the elaborate lobby design by Frank Lloyd Wright.

Other architects in 19th century America used oriel-like architecture to increase interior floor space and optimize natural light and ventilation in "the tall building," a new form of architecture that would become known as the skyscraper. For example, the architecture team of Holabird & Roche designed the 1894 Old Colony Building with all four corners protruding. The oriel towers start on the third floor and hang over the lot line or footprint of the building. The architects had cleverly found a way to use airspace to increase square footage beyond the property line.

Modern Definitions from the City of New York

Oriel windows have no strict or definitive definitions, so know how your locality defines this architectural construction, especially when you live in a historic district. The New York City Landmarks Preservation Commission offers these suggestions:

"Bay Window: A projecting form containing windows that rises from the ground or from some other support, such as a porch roof; see also oriel."

"Oriel: A projecting bay window carried on corbels or brackets."

"Turret: A small tower, usually supported by corbels."

Source: Glossary, "Frequently Asked Questions," NYC Landmarks Preservation Commission [accessed November 30, 2014]