Pilaster

The pilaster is an architectural element in classical architecture used to give the appearance of a supporting column and to articulate an extent of wall, with only an ornamental function. It consists of a flat surface raised from the main wall surface, usually treated as though it were a column, with a capital at the top, plinth (base) at the bottom, and the various other elements. In contrast to a pilaster, an engaged column or buttress can support the structure of a wall and roof above.

In discussing Leon Battista Alberti's use of pilasters, which Alberti reintroduced into wall-architecture, Rudolf Wittkower wrote, "The pilaster is the logical transformation of the column for the decoration of a wall. It may be defined as a flattened column which has lost its three-dimensional and tactile value."

A pilaster appears with a capital and entablature, also in "low-relief" or flattened against the wall.

Pilasters often appear on the sides of a door frame or window opening on the facade of a building, and are sometimes paired with columns or pillars set directly in front of them at some distance away from the wall, which support a roof structure above, such as a portico. These vertical elements can also be used to support a recessed archivolt around a doorway. The pilaster can be replaced by ornamental brackets supporting the entablature or a balcony over a doorway.

When a pilaster appears at the corner intersection of two walls it is known as a canton.

As with a column, a pilaster can have a plain or fluted surface to its profile and can be represented in the mode of any architectural style. During the Renaissance and Baroque architects used a range of pilaster forms. In the giant order pilasters appear as two-storeys tall, linking floors in a single unit.

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