Bordet er en meter langt.

Bordet is the definite singular form of et bord (a table / table).

In Danish, the definite article is usually added to the end of the noun:

• et bord = a table
• bordet = the table

So bordet already means the table.

You would use:

• bord only in certain expressions or dictionary form
• det bord when you want extra emphasis or when an adjective is involved, for example det store bord = the big table

In this sentence, bordet by itself is the normal form.

Because meter is a noun with common gender in Danish, so it takes en:

• en meter
• en kilometer
• en centimeter

The gender of meter is completely separate from the gender of bord.

So even though bord is a neuter noun (et bord), the measurement noun is still:

• en meter

not et meter.

Because lang has to agree with the noun it describes, and bord is a neuter noun:

• et bord
• therefore: langt

This is the same pattern as with many Danish adjectives:

• en lang vej = common gender
• et langt bord = neuter

In your sentence, langt is used after er, but the agreement still applies:

• Bordet er langt
• Bordet er en meter langt

So the -t is there because the subject is et bord.

That is a very common question.

When an adjective comes before a noun, definiteness matters:

• det lange bord = the long table

But here the adjective is predicative, meaning it comes after er:

• bordet er langt

With predicative adjectives, Danish mainly shows gender and number, not the same definite form used before nouns.

So:

• bordet er langt = singular neuter
• bordene er lange = plural

That is why langt is correct, even though bordet is definite.

Here it is an adjective, not an adverb.

It describes the table’s length, and it agrees with bordet. That is why it has the neuter -t ending.

This can be confusing because the adverb form of many Danish adjectives also ends in -t. But in this sentence, langt is clearly a predicative adjective:

• Bordet er langt = adjective
• Han løber langt = adverb

So even though the form looks similar, the grammar is different.

Because Danish normally expresses measurements like this:

• [subject] + er + [measurement] + [adjective]

So:

• Bordet er en meter langt
• Huset er ti meter højt
• Vejen er fem kilometer lang

The measurement phrase comes before the adjective. This is the standard and natural word order in Danish for dimensions.

In standard Danish, no — it should be langt.

Since bord is neuter (et bord), the adjective must match:

• et bord er langt
• bordet er en meter langt

Using lang would not match the gender correctly.

Yes, absolutely. The structure stays the same:

• Bordet er to meter langt
• Bordet er tre meter langt

Notice that langt does not change, because the subject is still bordet.

Also note that meter is the same form after these numbers:

• en meter
• to meter
• tre meter

Yes.

That would be the correct sentence if you mean a table in a general or indefinite sense:

• Et bord er en meter langt

Compare:

• Et bord = a table
• Bordet = the table

The rest of the sentence stays the same because bord is still neuter, so you still use langt.

A careful approximation is:

BOR-det er en MEH-der langt

A few notes:

• bordet is roughly BOR-det
• er is often pronounced very lightly, almost like air or a reduced uh/er depending on accent and speed
• meter is roughly MEH-der
• langt ends with a consonant cluster that may sound shorter and softer than an English speaker expects

In natural speech, Danish pronunciation is often more reduced than the spelling suggests, so listening to native audio is especially helpful for a sentence like this.