Corner

A corner is the point where two edges or lines meet, forming an angle. In geometry, a corner is typically called a vertex—the common endpoint of two line segments that bound a corner of a polygon or polyhedron. The angle at a corner can be described as interior or exterior, and its measure determines whether it is acute, right, or obtuse. In everyday language, corners occur at street intersections, at the inside of a room, and at the edges of objects.

In geometry, corners are essential for defining polygons and polyhedra. The set of corners of a polygon are its vertices; the sum of interior angles depends on the number of corners. A right corner has a 90-degree angle. In computer graphics and modeling, corners are often referred to as vertices and are used to define the shape of polygons and meshes.

In construction and design, corners influence structural integrity and aesthetics. Joints such as miter joints create clean corners in frames; chamfers or fillets modify sharp corners to reduce wear, improve safety, or enhance appearance. Some objects feature rounded corners, described by a corner radius, which softens the transition between adjacent edges.

As a verb, to corner means to trap someone or to gain exclusive control of a market or resource. The term can also describe approaching or occupying a corner in sports, driving, or navigation. Corners thus appear across mathematics, engineering, design, and everyday language.