The triangular wall section on each side is called a gable end. If you look at the roof from the front, you see a large, sloped rectangular roof section. If you look at the side, you see the edges ...

Side-gable homes have the entry on a slanted roof side. Dormers aren’t found on the gable, but windows can be on gables. The style of the roof above the window defines the style of a dormer window.