A high-resolution region of discretization embedded within a low-resolution region of a numerical model or analysis system. Fine resolution may be desired to focus on a mesoscale feature such as a tropical cyclone or on a geographical area of interest. In two-way nested grids, information is passed back and forth between the high- and low-resolution regions, in contrast with one-way grids in which information is passed merely from low- to high-resolution regions. See grid telescoping, variable resolution model.