der Vorhang
curtain
A piece of fabric that is hung in front of a window to provide privacy or protection from the sun.
Kannst du bitte die Vorhänge zuziehen? Es wird langsam dunkel.
Could you please close the curtains? It's slowly getting dark.

curtain
Loading your saved state.
curtain
A piece of fabric that is hung in front of a window to provide privacy or protection from the sun.
Kannst du bitte die Vorhänge zuziehen? Es wird langsam dunkel.
Could you please close the curtains? It's slowly getting dark.

The word 'Vorhang' (curtain) is made up of 'vor' (in front of) and an old form of 'hängen' (to hang). So it literally describes something that hangs 'in front of' something else, for example in front of a window or a stage.
Ein schwerer Samtvorhang hing vor der alten Eichentür.
A heavy velvet curtain hung in front of the old oak door.
With curtains at a window, specific verbs are used for opening and closing. You say 'die Vorhänge aufziehen' (to open the curtains) and 'die Vorhänge zuziehen' (to close the curtains).
Zieh bitte die Vorhänge auf, damit etwas Licht ins Zimmer kommt.
Please open the curtains so some light can come into the room.
In a theater context, there are fixed expressions. At the beginning of a performance, 'hebt sich der Vorhang' (the curtain rises), and at the end, 'fällt der Vorhang' (the curtain falls).
Das Publikum wurde still, als sich der rote Vorhang langsam hob.
The audience fell silent as the red curtain slowly rose.
The 'Eiserne Vorhang' (Iron Curtain) is a fixed historical term. It is almost always used with the definite article 'der' and the adjective 'Eiserne'. The most common phrase is 'der Fall des Eisernen Vorhangs' (the fall of the Iron Curtain).
Meine Großeltern erzählten oft von der Zeit vor dem Fall des Eisernen Vorhangs.
My grandparents often talked about the time before the fall of the Iron Curtain.
border / limit
'Grenze' and 'Vorhang' can both separate something, but in different ways. A 'Grenze' is a line between countries or areas, or in a figurative sense between possibilities. A 'Vorhang' is usually a piece of cloth, for example at a window or on a stage. Only in special contexts can 'Vorhang' also mean a political division, especially in the fixed expression 'Eiserner Vorhang' (Iron Curtain). The words can be confused when talking about separation in general. For a real line between countries or areas, use 'Grenze'; 'Vorhang' only fits for cloth or for this specific historical meaning.

Nach dem letzten Lied schließt sich der Vorhang auf der Bühne.
After the last song, the curtain closes on the stage.
An der Grenze zwischen den beiden Ländern müssen alle Autos kontrolliert werden.
At the border between the two countries, all cars have to be checked.