In ecclesiastical architecture, a ciborium ("ciborion": κιβώριον in Greek) is a canopy or covering supported by columns, freestanding in the sanctuary, that stands over and covers the altar in a basilica or other church. It may also be known by the more general term of baldachin, though ciborium is often considered more correct for examples in churches. Early ciboria had curtains hanging from rods between the columns, so that the altar could be concealed from the congregation at points in the liturgy. Smaller examples may cover other objects in a church. In a very large church a ciborium is an effective way of visually highlighting the altar, and emphasizing its importance. The altar and ciborium are often set upon a dais to raise it above the floor of the sanctuary.