​CEILING, in architecture, is the top, or roof, of an upper room, made of plaster, laid over laths nailed on the bottom of the joists of the upper room; or, where there is no upper room, on joists made for that purpose, which are therefore called ceiling-joists.

Plastered ceilings are in much greater use in England than in any other country of Europe; they are preferable to papered, or other ceilings, as they make a room not only lighter, but also prevent the dust from penetrating through crevices; lessen the noise from above; check the progress of accidental fires; and, during summer, contribute to cool the air.—See Mortar, and Plaster of Paris.