A flat, usually rectangular structure composed of a rigid material, such as wood, glass, or metal, fixed at right angles to a wall or other vertical surface and used to hold or store objects, Something, such as a projecting ledge of rock or a balcony, that resembles such a structure, A thin slab or plank, a piece of marble, slate, wood, or other material, generally long and narrow, fixed horizontally to a wall, and used for supporting small objects; in general, a narrow flat surface, horizontal or nearly so, and raised above a larger surface, as of a floor or the ground