colonnade

A colonnade is a sequence of regularly spaced columns that supports an entablature and often a roof, forming a covered walkway, porch, or vestibule. The columns may be freestanding or attached to a wall, and the arrangement can be a single row or multiple parallel rows, such as a double colonnade. When arches span the space between the columns, the structure is more commonly called an arcade; the term colonnade emphasizes the vertical supports of the design.

In classical architecture, colonnades serve both functional and ceremonial purposes. They frame entrances, line courtyards, and create sheltered approaches to buildings. A long colonnade surrounding a court is known as a peristyle, while a covered walkway along a building is a typical stoa in ancient Greek architecture. Columns can be of various orders, most commonly Doric, Ionic, or Corinthian, and may be constructed of stone, marble, or other materials.

Historically, colonnades appear in ancient Greece and Rome and were revived and elaborated in later periods. The Stoa of Attalos in Athens is a well-known example from the Hellenistic era. In the Renaissance and Baroque periods, colonnades were used to produce monumental approaches to churches and palaces, such as the Colonnade of St. Peter's Square in Vatican City, designed by Gian Lorenzo Bernini. In modern contexts, colonnades continue to serve as architectural elements that convey rhythm, order, and a sense of procession.

See also: arcade, peristyle, stoa, portico, cloister.