Terningen er grønn.

In Norwegian, the definite article is usually added to the end of the noun as a suffix.

• en terning = a die
• terningen = the die

So -en here is the definite ending for a singular common-gender noun.

This is one of the big differences from English: instead of the die, Norwegian often says die-the, structurally speaking.

The base form is terning.

Its common forms are:

• en terning = a die
• terningen = the die
• terninger = dice
• terningene = the dice

So in the sentence, terningen is the singular definite form.

It means one die.

This can be confusing for English speakers because English has the irregular pair die/dice. Norwegian is more regular here:

• singular: terning
• plural: terninger

So terningen er grønn refers to a single die, not several dice.

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

So:

• å være = to be
• er = is / are / am, depending on context

In this sentence, er means is:

• Terningen er grønn = The die is green

Norwegian verbs do not change for different persons the way English verbs do. So the same er is used with I, you, he, we, etc.

Because terning is a singular common-gender noun, the adjective matches that pattern in this kind of sentence.

Here are the usual forms of the adjective grønn:

• grønn = common gender singular
• grønt = neuter singular
• grønne = plural and some other contexts

Examples:

• En terning er grønn = A die is green
• Et hus er grønt = A house is green
• Terningene er grønne = The dice are green

Even though terningen is definite, the predicate adjective after er is still grønn, because it agrees with the noun’s gender and number, not with definiteness in the same way an adjective before a noun would.

Because grønn here comes after the verb er, not directly before the noun.

Compare:

• den grønne terningen = the green die
  
  • here the adjective is placed before the noun, so it takes the form grønne
• terningen er grønn = the die is green
  
  • here the adjective is a predicate adjective after er, so it stays grønn

This is a very important difference in Norwegian adjective forms.

Yes. It is completely normal.

The structure is:

• Terningen = subject
• er = verb
• grønn = adjective describing the subject

So the pattern is basically:

Subject + verb + complement

This is very similar to English:

• The die is green

Terning is a common-gender noun in Bokmål.

That matters because gender affects:

• the indefinite article
• the definite ending
• adjective agreement

So:

• en terning = a die
• terningen = the die
• grønn = green, in the common-gender singular form

If the noun were neuter, the adjective form would be different:

• et hus = a house
• huset er grønt = the house is green

The hardest part for many English speakers is ø.

A rough guide:

• grønn sounds somewhat like grurn or grern, but not exactly
• the ø is a rounded vowel that English does not really have
• the final nn is pronounced clearly

A useful tip: try saying a vowel like in bird in some English accents, but with rounded lips.

Also:

• grønn = singular common gender
• grønt = neuter
• grønne = plural / other agreeing forms

So learning the pronunciation together with the adjective forms can help.

Yes, if it is already clear what you are talking about.

• Terningen er grønn = The die is green
• Den er grønn = It is green

Here den is the pronoun it for a common-gender noun like terning.

So once terningen has already been mentioned, Norwegian often switches to den just like English switches to it.