A dual lattice results from an original one by assigning cells to each of the original nodes. The cell around each node includes all point that are closer to the node than to any other node. The resulting lattice is the dual of the original one. The dual of the dual is the original lattice.
Some well known duals:
|voronoi triangulation||Delaunay triangulation|
|square lattice||square lattice (it's self-dual)|
|triangular lattice||honeycomb lattice|