Tempered glass
Heat-treated safety glass that breaks into small pebbles instead of sharp shards. It's required in doors and many places near doors, floors, and wet areas. It can't be cut after it's made, so it's ordered to size.
Laminated glass
Two layers of glass bonded to a plastic interlayer. If it breaks, it tends to stay together in the frame. It can also reduce outside noise.
Obscure and textured glass
Frosted or patterned glass that lets light in while blocking a clear view. Common in entry sidelights, transoms, and bathroom windows.
Single-pane and double-pane
Single-pane glass is one layer, common in older homes. Double-pane units are two panes sealed together with a gap between them, which insulates better and can make a room quieter. See single-pane reglazing and double-pane replacement.
Thicker glass
Large panes need thicker glass to handle wind and their own weight. We size the glass to the opening when we measure.