In architecture, plaster is a type of material used to create a smooth, flat surface on walls and ceilings. Plaster is made from a mixture of water, sand, and either lime, cement, or gypsum, which is applied to a surface and then smoothed and allowed to dry. Plaster can be applied in a variety of textures and finishes, such as smooth or rough, and can also be molded into decorative shapes and patterns. It is a versatile material that has been used in architecture for centuries and is still commonly used today in both traditional and contemporary designs. Plaster is also known for its durability and fire resistance, making it a popular choice for building interiors and exteriors.