In classical architecture, a pilaster is a square pillar, sometimes standing free, but usually attached to a wall, from which it projects one-fifth, one quarter, or some other definite proportion of its breadth. Greek pilasters, or antae, were of the same breadth from top to bottom, and had different capitals and bases from those of the orders with which they were associated. The Romans gave them a taper like the columns, and the same capitals and bases.