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 can open inward or outward, creating a wide entryway. They are often used in homes to connect living spaces or to provide access to patios and gardens. French doors can be made from various materials, including wood, fiberglass, or vinyl, and are available 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.