paperboard, material similiar in shape and composition to paper, but generally thicker, stronger, and more rigid. Paper machines, e.g., Fourdrinier machines, are used to make sheets of paperboard. Sometimes these machine-made sheets are pasted to each other or to paper sheets to build up special thicknesses. The function of a particular type of paperboard is often indicated by its name, e.g., boxboard. Paperboard can be made into a wide variety of items, including folding cartons, advertising displays, electrical insulators, and coasters.