- A panel formed by bonding two thin facings to a thick, and usually lightweight, core. Typical facing materials include plywood, single veneers, hardboard, plastics, laminates, and various metals, such as aluminum or stainless steel. Typical core materials include plastic foam sheets, rubber, and formed honeycombs of paper, metal, or cloth.
- A prefabricated panel that is a layered composite formed by attaching two thin facings to a thicker core. An example is precast concrete panels, which consist of two layers of concrete separated by a nonstructural insulating core.