What is the term for an arch rotated 180 degrees on its axis?

The term for an arch rotated 180 degrees on its axis is a "catenary arch." This shape is derived from the mathematical curve known as a catenary, which describes the ideal form of a hanging chain or cable when supported at its ends and acted upon by gravity. When this curve is rotated 180 degrees, it creates an arch that is often used in architecture and engineering for its structural efficiency.