Voronoi diagram
(Or "Voronoi tessellation", "Voronoi decomposition", "Dirichlet tessellation", After Georgy Feodosevich Voronoy) For a set S of points in a Euclidean space, the partition Vor(S) of the plane into the voronoi polygons associated with the members of S, where each polygon is defined by the set of points nearer to some given point in S than to any other point in S.
The Voronoi diagram is the dual of the Delaunay triangulation of S.