Theatre drapes and stage curtains are the big pieces of fabric that you see hanging on the stage when you go watch a play or a musical!
There are different types of drapes and curtains, and they play different roles during a performance. For example, the big curtain that you see at the beginning and end of the show is called the "main drape" or "grand drape". It hides the stage from the audience before the show starts and then opens up to reveal the stage when the show begins.
Other drapes and curtains are used during the performance, to change the scenery or create different moods. For example, a drape called a "scrim" is semi-transparent and can be lit from behind. This creates a special effect where the audience can see a scene behind the scrim, but then the lighting changes and the scene disappears!
There are also "legs" and "borders" which are drapes that are used to hide the offstage areas and create a framing effect around the actual performance space.
Overall, theatre drapes and stage curtains are like giant pieces of fabric that help create the magic of a theatre performance!