Gable fronted dormer: Also called simply a gabled dormer, this is the most common type. It has a simple pitched roof of two sloping planes, supported by a frame that rises vertically to form a triangular section below the roofline, i.e. a gable.
Wall dormers aren't surrounded by roof, as most dormers are. Instead, as their name implies, they rise from a wall. Except for this feature, though, they span the full range of dormer styles, from arched top to shed roof to hip roof. Wall dormers are found in houses of many styles, including Gothic Revival, Romanesque and Mission.