Sheetrock, gypsum board, and drywall are essentially the same material, with slight differences. Sheetrock is a brand name for gypsum board, and both consist of a gypsum core sandwiched between paper layers, used for interior walls and ceilings. Drywall is the general term for these panels. Plaster, however, is a different material applied wet over a base (like lath) and hardens to create a smooth, durable finish. Plaster is more labor-intensive and time-consuming to install compared to drywall.