**INTRADOSSO (from the French intrados).** - Technical term in architecture, meaning “soffit,” indicating the inner, curved surface of arches and vaults. The classification of arches depends on the form of the curve of the intrados; they are called semicircular when the curve is represented by a semicircumference whose chord is the horizontal diameter passing through the springing points; segmental when the curve is not a complete semicircumference or is polycentric, with the centre of the central curved segment situated below the level of the springing points; pointed when the curve of the intrados consists of two circular arcs forming a point and having their centres, usually, at two-thirds of the span; stilted when the centre of the curve lies above the springing lines.
The curve of the intrados assumes a particular form in ogee and keel arches, which are infrequently used in architectural practice.
Another kind of intrados is the multifoil type, characteristic of Islamic architecture (for example, the church of the Corpo di Gesù in Segovia and the mosque of Cordova).