Stucco is a material that's used to coat ceilings, walls, and the exterior of buildings. If you travel to the southwestern United States, you'll see many homes with stucco exteriors and terra-cotta roof tiles.
Stucco is a type of plaster, a substance that goes on as a wet paste and dries hard. In fact, in Italian, stucco means "plaster," from a Germanic source it shares with the Old High German stukki, or "crust." Stucco is mainly decorative, often covering metal or cinderblock, but it's also a weather-resistant coating. While regular plaster is usually smooth and white, stucco is most often textured.