The term 'THIN LAYER; COVERING' can be used to describe a COATING, which is a type of material that is applied to the surface of an object in order to protect it from damage or to enhance its appearance. A thin layer of COATING is one that is applied in a very thin layer, usually less than 1 millimeter thick. This type of COATING is often used to provide a protective barrier against water, dust, and other environmental elements. It can also be used to add color or texture to an object.