A curtain is a piece of cloth used to block light, water, or cold air from entering a place (some curtains are better at blocking than others because of the type of fabric used). Curtains are hung around showers to keep water off the floor around the shower. Curtains are also hung around windows to keep light from coming in. A curtain is raised and lowered during a play or other theatrical production. Curtains can come in many different colors and different types of fabric. It is also originally a French word.