In the past, columns were used in home building to provide structural support to ceilings. While these structural columns aren't found in most modern homes, smaller units are often used to mimic the look and style of classic column design. Thinner columns are referred to as pillars or pilasters; these are typically used for decorative purposes. While many builders use these terms interchangeably, pilasters are usually recessed into a wall while pillars are surface-mounted or free-standing [source: Kalyn].
A pillar or pilaster can be used to frame a fireplace, doorway or other opening. These units are also a useful tool for highlighting a piece of artwork or an architectural feature within a room.
Most pillars and pilasters are styled after ancient Greek and Roman column designs. They're made up of three components: a crown, shaft and plinth, or base. Many manufacturers sell interchangeable units to allow homeowners to mix and match different styles to create a unique look. Wood and plaster versions are the most common, though fiberglass offers an attractive and cost-effective alternative for those on a budget.