A buttonhole is a reinforced hole in fabric that a button can pass through, allowing one piece of fabric to be secured to another. The raw edges of a buttonhole are usually finished with stitching. This may be done either by hand or by a sewing machine. Some forms of button, such as a frog, use a loop of cloth or rope instead of a buttonhole.
Machine-stitched keyhole buttonhole with bar
A machine-made buttonhole.
A bound buttonhole. The inset fabric panels are called welts.
A button is a fastener that joins two pieces of fabric together by slipping through a loop or by sliding through a buttonhole.
Brass buttons from the uniform of a Danish World War I artillery lieutenant
Modern buttons made from vegetable ivory
Spanish button (approx. 12 mm) from ca. 1650–1675
Button stamping machine at the Henri Jamorski Button Factory in Paris, 1919