Artistgarderoben er stengt.

Because Norwegian normally writes compound nouns as a single word.

So:

• artist
  • garderobe → artistgarderobe
• definite form: artistgarderoben

English often uses separate words, but Norwegian usually joins them. Writing artist garderoben would look wrong in standard Norwegian.

The ending -en is the definite article attached to the noun.

Compare:

• en artistgarderobe = a dressing room
• artistgarderoben = the dressing room

This is very common in Norwegian: instead of putting the before the noun, Norwegian usually adds a definite ending to the noun itself.

It is singular.

The ending -en here marks definite singular. So it means the dressing room, not the dressing rooms.

A plural form would look different, for example:

• artistgarderober = dressing rooms
• artistgarderobene = the dressing rooms

No. In Norwegian, this is a compound noun, not a possessive form.

English often says things like:

• artist’s dressing room
• staff room
• hotel room

Norwegian usually builds these ideas with compounds instead:

• artistgarderobe
• pauserom
• hotellrom

So artist- describes what kind of garderobe it is.

Er is the present tense of å være (to be).

So:

• er = is / are / am, depending on context

In this sentence it links the subject to its description:

• Artistgarderoben
  • er
    • stengt

That is the normal equivalent of English The dressing room is closed.

Here stengt functions like an adjective meaning closed / shut.

It comes from the verb å stenge (to close, shut), but in sentences like this it is used to describe a state:

• Døren er stengt.
• Butikken er stengt.
• Artistgarderoben er stengt.

So even though it comes from a verb, you can think of it here as the descriptive word after er.

Because stengt is the normal singular form used here.

With this word, you will often see:

• singular: stengt
• plural: stengte

For example:

• Døren er stengt.
• Dørene er stengte.

So in Artistgarderoben er stengt, the singular form is correct.

Yes. This is a very basic Norwegian sentence pattern:

• Subject + verb + complement

So:

• Artistgarderoben = subject
• er = verb
• stengt = complement

It works just like standard English word order in a simple statement.

Normally, no.

Without the definite ending, artistgarderobe is just the bare noun stem, and that does not work naturally by itself as the subject here.

You would usually need either:

• En artistgarderobe er stengt. = A dressing room is closed.
• Artistgarderoben er stengt. = The dressing room is closed.

In most real situations, the definite form sounds much more natural.

It usually means closed / shut, not specifically locked.

So it tells you the room is not open for use or access, but it does not necessarily say anything about a lock.

If you specifically wanted to say locked, Norwegian would more naturally use words related to låst.

Yes, you could, but stengt is usually the more natural choice for places, rooms, shops, doors, and similar things that are not open.

Very roughly:

• stengt = closed/shut, often for access or opening status
• lukket = closed, but sometimes more formal or more literal depending on context

So Artistgarderoben er stengt sounds very natural.

No. Norwegian does not capitalize all nouns.

It is capitalized here only because it is the first word of the sentence.

If the same noun appeared in the middle of a sentence, it would normally be lowercase:

• Jeg tror artistgarderoben er stengt.