A material capable of fastening together two other materials by means of surface attachment. The terms glue, mucilage, mastic, and cement are synonymous with adhesive. In a generic sense, an adhesive is any material capable of fastening by means of surface attachment, and thus includes inorganic materials such as portland cement and solder. Practically, however, adhesives are a broad set of materials composed of organic, primarily polymeric materials that can be used to fasten two other materials together. The materials being fastened are often called adherends, and the resulting assembly is called an adhesive joint or adhesive bond.