Grid (spatial Index)
In the context of a spatial index, a grid (a.k.a. "mesh", also "global grid" if it covers the entire surface of the globe) is a regular tessellation of a manifold or 2-D surface that divides it into a series of contiguous cells, which can then be assigned unique identifiers and used for spatial indexing purposes. A wide variety of such grids have been proposed or are currently in use, including grids based on "square" or "rectangular" cells, triangular grids or meshes, hexagonal grids, grids based on diamond-shaped cells, and possibly more. The range is broad and the possibilities are expanding.
Read more about Grid (spatial Index): Types of Grids, Grid-based Spatial Indexing, Other Uses