In mathematics, a vertex is a point where two or more curves, lines, or edges meet. It is a corner point of a polygon, polyhedron, or other higher-dimensional polytope, formed by the intersection of edges, faces, or facets of the object. The plural of vertex is vertices. For example, in a square, each of the four corners is a vertex. In a parabola, the vertex is the peak in the curve. The concept of vertex is fundamental in geometry and is used to describe angles.