👉 The term "concave" refers to a shape or object that is not flat but instead has a curved surface. It is often used in geometry and physics to describe a curve where points are closer to one side of the curve than at the other. Here's an example: In geometry, a concave polygon is defined as a closed figure formed by connecting line segments with endpoints on two or more sides that do not all lie on the same plane. These segments are often called "vertices" and
