Surface (geometry)

A surface is a concept in Euclidean geometry that has length and breadth but no depth. Any set of points which is topologically equivalent to a subset of a plane is a surface: this includes curved surfaces such as a paraboloid, infinite surfaces such as a plane, surfaces of limited extent such as the interior of a polygon, and surfaces with strange topology such as an infinitely long row of squares each separated by some distance, or the set of all points with rational coordinates in a plane. A surface is made up of an infinite number of lines or curves (curved lines). The extremities of a solid are made up of surfaces.