in Architecture, any thing that adorns and enriches a building, church, triumphal arch, or the like, either without or within.

Decoration is more particularly applied to the scenes of theatres. In operas and other theatrical performances, the decorations must frequently be changed, conformably to the subject. The ancients had two kinds of decorations for their theatres: the one, called versatiles, having three sides or faces, which were turned successively to the spectators; and the other, called ductiles, showing a new decoration by drawing or sliding another before it. This latter sort is still used, and apparently with much greater success than among the ancients, who were obliged to draw a curtain whenever they made a change in the decorations; whereas on our stage the change is made in a moment, and almost without its being perceived.