Gull-wing Doors are doors that hinge from the roof as opposed to the conventional way of being hinged at the A or B post of the cars body. The name derives from the image obtained when the doors are in the up position and having the similarity to a seagulls wings in flight and were first used by Mercedes Benz in the early fifties on the 300SL race car.
Gull-wing Doors have advantages and disadvantages. The advantage is that in tight parking spaces they require much less room to open than a conventional door and allow much better access for entering and exiting the vehicle. The downside is that in the event of an accident and the vehicle should end up on it's roof then the doors become impossible to open and escape only viable through the windscreen.
Many manufacturers over the years have used the Gull-wing design and are also very popular in the Kit Car and Custom scene.