Byen er enorm.

Because Norwegian usually puts the definite article at the end of the noun.

• by = city / town
• byen = the city

So -en here means the. This is very different from English, where the comes before the noun.

The base form is by, which means city or town.

Its forms are:

• en by = a city
• byen = the city
• byer = cities
• byene = the cities

So in this sentence, byen is the definite singular form.

Er is the present tense of the verb å være = to be.

In Norwegian, the present tense verb does not change depending on the subject:

• jeg er = I am
• du er = you are
• byen er = the city is
• de er = they are

So er works for all persons in the present tense.

Here, enorm is a predicate adjective because it comes after er.

In Norwegian, adjectives used after verbs like er, blir, and virker often agree with the noun, but for many adjectives the common-gender singular form has no ending, which is what you see here.

Since byen is singular and common gender, enorm is correct.

Compare:

• en enorm by = a huge city
• byen er enorm = the city is huge

If the subject were neuter, you would usually get:

• huset er enormt = the house is huge

And plural:

• byene er enorme = the cities are huge

Because enorm is not a noun here; it is an adjective describing byen after the verb er.

In English, you also do not say the city is a huge. You just say the city is huge.

So:

• byen er enorm = correct
• byen er en enorm = incorrect, because enorm is not being used as a noun

This is the normal word order for a simple statement:

• subject + verb + adjective

So:

• Byen = subject
• er = verb
• enorm = adjective

Norwegian main clauses usually keep the verb in the second position. In this short sentence, that gives you the same basic order as English.

A rough guide is:

• Byen ≈ BEE-en or BY-en, depending on accent and how narrowly you describe it
• er ≈ a short air / ehr
• enorm ≈ eh-NORM

A few useful notes:

• The y in by is a Norwegian vowel that English does not really have.
• Byen is often pronounced smoothly, almost like two connected parts: by-en.
• The r in Norwegian varies by dialect.

If you want a simple learner-friendly approximation, BY-en er eh-NORM is a decent start, but the real vowel in by is not exactly English y.

By is usually treated as a common gender noun in Bokmål, so you normally say:

• en by
• byen

Norwegian Bokmål has common gender and neuter in everyday grammar, although many people also talk about traditional masculine and feminine patterns. In practice, for by, learners should use en by and byen.

Yes. Stor means big / large, while enorm means enormous / huge.

So the difference is mainly strength:

• Byen er stor = The city is big
• Byen er enorm = The city is enormous

Enorm sounds stronger and more emphatic than stor.

Yes. By can mean either city or town, depending on context.

That means byen could be translated as the city or the town in some situations. The exact English choice depends on what kind of place is being talked about.