In architecture, a pendentive is a constructional device permitting the placing of a circular dome over a square room or of an elliptical dome over a rectangular room.^[1] The pendentives, which are triangular segments of a sphere, taper to points at the bottom and spread at the top to establish the continuous circular or elliptical base needed for a dome.^[2] In masonry the pendentives thus receive the weight of the dome, concentrating it at the four corners where it can be received by the piers beneath.

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Prior to the pendentive's development, builders used the device of corbelling or squinches in the corners of a room. Pendentives commonly occurred in Orthodox, Renaissance, and Baroque churches, with a drum with windows often inserted between the pendentives and the dome. The first experimentation with pendentives began with Roman dome construction in the 2nd–3rd century AD,^[3] while full development of the form came in the 6th-century Eastern Roman Hagia Sophia at Constantinople.^[4]

• A pendentive, labelled A. Illustration of a church in Nantua.
• Formation of a pendentive. Eugène Viollet-le-Duc, 1856
• Pendentive structure
• Arches (left and right), dome (top) and pendentive (centre) in Moscow Cathedral
• Holy Trinity Church, Fulnek, Czech Republic
• Church of St. Clement of Ohrid, Skopje, North Macedonia
• One pendentive of the Hagia Sophia main dome
• Pendentive of the Church of Saint Sava main dome, Belgrade, Serbia
• Vision of St. John on Patmos (1520–1522, Correggio, San Giovanni Evangelista, Parma), part of which is painted on the pendentives

• History of Italian Renaissance domes
• Spandrel – Space between a curved figure and a rectangular boundary