A French door is a type of door that features multiple small panes of glass, allowing natural light to flow between rooms or to the outside. Typically, these doors are hinged and open outward or inward, creating a wide entryway. They are often used in homes to connect living spaces, such as a dining room to a patio or garden. French doors can be made from various materials, including wood, fiberglass, or vinyl, and they come in different styles to match home decor. They are popular for their aesthetic appeal and ability to enhance the feeling of openness in a space, making them a favored choice in modern architecture.