springer
n. countable C2 Proficiency US //ˈspɹɪŋɝ// UK //spɹˈɪŋɐ// springer
n. the first stone of an arch that sits on top of a wall or pillar. It is the point where the curve of the arch begins.
n. the lowest stone in an arch or vault, resting directly on the impost or pier. It marks the point where the vertical support transitions into the curve of the arch.
The mason carefully placed the springer on the pillar.
Architects must ensure the springer is perfectly level to support the weight of the entire stone arch.
In Gothic architecture, the springer often serves as the base for multiple ribs that fan out across the ceiling to form a complex vaulted structure.
Usage
Commonly used in technical architectural descriptions of masonry and vaulting.