A grid is a data structure commonly used to represent map features. A cellular-based data structure composed of Cells or pixels arranged in rows and columns (also called a "raster").
Grid means A geographical zone for reporting and displaying emissions information. Grid sizes vary depending on their use. For example 100 km has been used for displaying emissions maps of Canada, but for ambient air quality modeling, grid sizes of 4 km or even 1 km may be used.
List of books: Grid
Other /More definition:
Grid is a A network of lines arranged in a systematic pattern with each delineated component being of equal size.