Stoffet er grått.

It marks the noun as definite singular for a neuter noun.

• stoff = the basic dictionary form
• stoffet = the
  • noun

So Norwegian often expresses the by adding an ending to the noun, instead of using a separate word before it.

Yes. Stoff is neuter.

That matters because neuter nouns typically use:

• et in the indefinite singular: et stoff
• -et in the definite singular: stoffet

It also affects adjective agreement, which is why you get grått here.

Because the adjective has to agree with the noun.

Since stoff is neuter singular, the adjective takes the neuter singular form:

• common gender singular: grå
• neuter singular: grått
• plural: grå

So:

• en bil er grå
• et stoff er grått
• biler er grå

That is simply the correct written neuter form of grå.

Some Norwegian adjectives form the neuter with -tt, especially short adjectives like:

• grå → grått
• blå → blått
• rå → rått

So even though you may think of it as adding a neuter -t, the actual standard spelling here is grått.

Because Norwegian usually attaches the definite article to the noun itself.

Compare:

• English: the material
• Norwegian: stoffet

This is one of the big structural differences from English. Instead of putting the before the noun, Norwegian often puts definiteness at the end.

Because grått is being used after the verb er. That is called a predicative adjective.

Predicative adjectives in Norwegian normally agree with the noun in gender and number, but not in definiteness in the same way adjectives before nouns do.

Compare:

• stoffet er grått
  adjective after the verb

• det grå stoffet
  adjective before the noun

So after er, grått is exactly what you expect for a neuter singular noun.

Yes, very similar.

The structure is:

• Stoffet = subject
• er = verb
• grått = adjective/complement

So it follows the pattern:

subject + verb + adjective

This makes the sentence quite straightforward for an English speaker.

Er is the present tense of å være, which means to be.

So:

• å være = to be
• er = is / are

In this sentence, er means is.

It changes depending on the gender and number of the noun.

Examples:

• Bilen er grå.
  common gender singular

• Huset er grått.
  neuter singular

• Bilene er grå.
  plural

• Husene er grå.
  plural

So grått is specifically the form used with a neuter singular noun.

You invert the subject and the verb:

Er stoffet grått?

This is very common in Norwegian yes/no questions.

• statement: Stoffet er grått.
• question: Er stoffet grått?

They use the adjective in two different ways.

• stoffet er grått
  = the adjective comes after the verb and describes the noun
  this is a predicative use

• det grå stoffet
  = the adjective comes before the noun and is part of the noun phrase
  this is an attributive use

So both involve the same noun and adjective, but the grammar is different.

A simple learner-friendly guide would be:

• stoffet ≈ STOFF-eh
• grått has a long vowel like groht with a rounded å sound

A few useful points:

• å is not the same as English a
• the final -et in many words is often pronounced like a short unstressed eh
• double consonants in spelling often signal that the preceding vowel is short

If you are learning pronunciation, it helps to listen to native audio for both stoffet and grått, since the å sound is especially important.