Glossary · P
Pendentive
Also called pendentives
A curved triangular surface (part of a sphere) that fills the corner between two arches and carries a circular dome or drum over a square bay. The sphere passes through the corners of the square; the pendentives are the parts of it left inside the square below the circle inscribed in it.
Rules that use the word
The pendentive: a sphere cut by a square. To set a round dome on a square bay, imagine a sphere passing through the four corners of the square; cut it by the four vertical planes of the sides and by the horizontal plane of their crowns. The four spherical triangles left in the corners are the pendentives; the circle at their top carries the dome.
The sail vault: one sphere, uncut. If the sphere that forms the pendentives is simply continued above the ring, the bay is covered by a single shallow dome, the sail vault or pendentive dome, which springs directly from the four corners.
Raise the dome on a drum. Lift the dome on a cylindrical or polygonal drum pierced with windows between the ring of the pendentives and the springing of the dome, to light the centre of the church and to make the dome visible from afar.
Where it appears in the book
In the chapters Domes, Byzantium and the Early Church.
A feature of Byzantine architecture.
Nearby in the glossary
Patte d’oie · Pattern language · Pedestal · Pediment · Pergola · Peripteral · Peristyle · Perpendicular tracery