Adhesive, any substance that is capable of holding materials together in a functional manner by surface attachment that resists separation. “Adhesive” as a general term includes cement, mucilage, glue, and paste—terms that are often used interchangeably for any organic material that forms an adhesive bond.

Industrial adhesives are organic and inorganic chemical compounds that are used to join components. Products include acrylic, epoxy, hot melt, polyurethane, silicone, thermoset, and UV curing adhesives, as well as industrial sealants. Most industrial adhesives are used in fastening applications.