Folding doors, are often referred to with other terms such as; 'bi-folding', 'accordion', or 'Nana Walls'. While there are a number of different manufactures and configurations for these types of doors, one thing remains the same: they are referring to door panels that slide and fold up to be out of the way.
Fusion of Space
Folding doors can even be made as folding windows, or adjoining doors that meet at a corner, to open up even more of a floor plan.
Photo Courtesy of LaCantina Doors