A1: Tempered glass (AKA safety glass) is heat-treated so it breaks into tiny pieces instead of large shards. It is also stronger than regular (annealed) glass, generally four times stronger. It is also required by law in some locations such as doors, showers, and glass less than 20 inches from the ground or a door.
A2: A grid pattern is the decorative lines that may be inside a dual-pane window creating the appearance of little windows. These are also called muntins or French windows.