Binder boards are essential materials in bookbinding. The board's durability and stiffness make it perfect for use in creating hardcover books, storage boxes, and archival materials. There are several synonyms for binder board, including bookboard, caseboard, and millboard. Bookboard is commonly used in bookbinding, and it is made from several materials like cotton, linen, or wood. It is also available in different thicknesses to suit various book sizes. Caseboard is another synonym for binder board. It is thick and tough, making it suitable for creating hardcover book covers. Lastly, millboard is a type of binder board that is commonly used in archival materials to protect them from wear and tear.