Adhesive substance resembling gelatin , extracted from animal tissue, particularly hides and bones, or from fish, casein (milk protein ), or vegetables.
Glue was used as early as 3000 BC in wooden-furniture construction in Egypt. Synthetic resin adhesives such as the epoxies are replacing glue for many uses, but glue is still widely used as an adhesive in woodworking and in certain manufacturing and other industrial processes.