What architectural feature is defined as a series of arches supported by piers or columns?

The architectural feature defined as a series of arches supported by piers or columns is known as an arcade. An arcade consists of multiple arches, which can create a covered walkway or a passageway. This element not only serves aesthetic purposes but also provides structural support for the building. The piers or columns play a crucial role in distributing the weight of the arches above.

In contrast, a baluster is a short post or pillar that supports a rail, commonly used in staircases and balconies, and does not form a series of arches. A cupola is a small dome that often crowns a larger structure, adding to its visual appeal but is not associated with a series of arches. A pendentive, on the other hand, is a curved triangle that transitions the space between a square room and a dome, facilitating the support of the dome but is not characterized by arches and columns like an arcade. Thus, the definition and function of an arcade are distinct and integral to understanding classical architecture.