A pediment is a gable supported by a set of columns, pilasters, or caryatids. Pediments are almost always symmetrical, with a peak in the center, and much wider than their height. Most pediments are triangular, but some are bowed, curled, or "broken" by one or more notches.

Pediments can rest on top of a row of evenly spaced columns, or they can be supported by columns flanking a portal (an entryway or a window), or even flanking a solid wall.

Pediments are especially common in Classical Greek, Classical Roman, Renaissance, Mannerist, Baroque, Neo-Classical, Neo-Renaissance, Neo-Baroque, and Postmodern architecture.