Architectural design has its own language. There are all kinds of terms we architects throw around on a regular basis that make the non-architects in the world scratch their heads. We find the less translation we have to do with our clients, the more fluid the design process can be. Therefore, we’ll begin dappling our blog posts with some Architectural Design Terms for Newbies. That way, you’ll have a better idea of what your architect is talking about when she mentions something, like – say – a pendentive arch.

Arches come to us by way of the Romans. They were the first engineers of these visually pleasing and graceful architectural features. However, like most great human inventions, arches and domes have gone through their own evolutionary process. The first technique for placing a dome on top of a square space was to create four arches with ordinary walls on top, called squinches, that could support the dome. A pendentive is a construction device that allows us to build a round dome over a square space, or an elliptical dome over a rectangular space, without the use of squinches.

Dome supported by squinches

Dome supported by squinches. Source:


The Byzantines created a more elegant, but more geometrically complex solution to the squinch. Rather than using regular walls over the arches, the Byzantines used spherical triangles to fill the space above the arch. The effect is breathtaking.

pendentive arch in cathedral

Pendentive arch. Source:



This is not a church….this is not a courthouse…this is someone’s cottage!

While pendentive arches were more commonly used in roman cathedrals, the one pictured here is in a residential “cottage,” (the term that was used for the Newport mansions).

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