A curtain is a piece of cloth intended to block or obscure light. Curtains are often hung on the inside of a building's window to block the travel of light, for instance at night to aid sleeping, or to stop light from escaping outside the building (stopping people outside from being able to see inside, often for privacy reasons). In this application they are also known as "draperies." Curtains come in a variety of shapes, materials, sizes, colours and patterns, and they often have their own sections within department stores, whilst some shops are completely dedicated to selling curtains.

Curtains also provide visual separation in other situations such as on a performance art stages where the actors make final preparations for the show behind the curtain while the audience waits in front of the curtain. If used for a particular performance, the curtain typically opens when the show begins and closes for substantial pauses in the performance.

The curtain played a special role in Jewish and Christian history. A curtain separated the holy place, reserved for priests, from the most holy place, reserved exclusively for the Ark of the Covenant in the temple in Jerusalem (Exodus 26:31-33). In the New Testament, as Jesus died, "the curtain of the temple was torn in two," symbolizing humanity's connection to God through the death of Jesus (Luke 23:45).

See also

• Shower curtain
• Window blinds

Curtain is also the title of a novel by Agatha Christie, written in the 1930s but published posthumously in 1975. It is the last novel featuring the detective Hercule Poirot, and has the same setting as the first, The Mysterious Affair at Styles.

Curtains is the title of a song by Peter Gabriel as part of the Ubisoft game MYST IV Revelation. The song and accompanying animation are designed to show the player that they are no longer in the same setting as the rest of the game (or normal reality in general).