French doors appear to have originated in France at the latter end
of the Renaissance period of art and architecture, with a growth of
popularity rising in France and Germany. A French door is also known as a French window, and refers to a door that has multiple windows set into it, the full length of the door.These windows are also known as “lites”, and are rather popular for allowing maximum light to enter and permeate a home. Traditionally, French doors are constructed with multiple individual sections of glass and mullions. Mullions are the dividing bars between window lites or panels. French Doors are also known as true divided lite French doors, or TDL.