In graph theory, another name for a node.
The Voronoi diagram of a collection of disjoint objects (often called sites) in some metric space is a partition of that space into cells corresponding to the sites such that the points in each cell are closer to the corresponding site than to any other site. Also known as a Dirichlet tesselation, especially when the sites are the points of a lattice. The cells of the diagram are also known as Thiessen polytopes.