The vault gusset is the three-dimensional curved area between the arches of a vault .
The hanging gusset ( pendentif ) is the transition between a circular shape and a square or polygonal base.
Arch bridges with elevated roadways are referred to as closed or open grooves , depending on whether the spaces between the roadway and the arch on the other side of the apex are filled.
- Wilfried Koch: A brief history of building history. Orbis, Munich 1991, p. 220.