"extrados"的定义和意义

What is the "extrados"?

In architecture, the extrados refers to the outer curve or surface of an arch. It is the upper part of the arch that forms a smooth, rounded shape, contrasting with the inner curve known as the intrados. The extrados is important in the overall design of an arch, contributing to its aesthetic appearance and structural stability. This feature can be visible in various architectural styles and is often made from materials like stone or brick, adding beauty and character to buildings and structures.