Definition & Meaning of "impost"

What is an "impost"?

In architecture, an impost is a horizontal surface or ledge at the top of a column or wall that supports an arch or vault. It serves as a transition between the vertical support and the curved shape of the arch, helping to distribute weight evenly. Imposts can vary in design, ranging from simple to highly decorative, and are often made from materials like stone or brick. This element not only provides structural support but also enhances the visual appeal of architectural features, contributing to the overall style and character of a building.