Definition - What does Grid System mean?
A grid system in graphic design uses a two-dimensional framework to align and lay out design elements. Breaking down a single design space into a grid can help position individual components in ways that can catch the eye, create a user flow and make information and visuals more appealing and accessible to audiences.
Techopedia explains Grid System
Many grid systems are composed of boxes, squares and rectangles. Design components can be placed within these boxes to achieve layout goals. Other types of grids include more diverse geometric shapes, and can be used on asymmetric designs such as a picture of a human or animal. In either case, the grid system utilizes geometric lines to break down the total space into a set of geometric components. Graphic design elements are then applied to each of these areas, to create a unified result.