A bi-fold is a type of door or window that consists of two panels that fold in half when opened. This design allows for a wide opening, making it ideal for connecting indoor and outdoor spaces. Bi-fold doors are commonly used in homes and commercial buildings to enhance natural light and provide a seamless transition between areas. Typically made from materials like wood, aluminum, or vinyl, bi-fold doors can be customized to fit various architectural styles. They are often used in patios, balconies, and large openings, offering both aesthetic appeal and functional benefits, such as improved ventilation and accessibility.