Nattavgangen begynner ved fergeterminalen.

Because Norwegian very often makes compound nouns by joining words together.

Here, nattavgangen is built from:

• natt = night
• avgang = departure
• -en = the definite ending

So:

• nattavgang = night departure
• nattavgangen = the night departure

This is very normal in Norwegian. Where English often writes two words, Norwegian often prefers one compound word.

The ending -en marks the noun as definite: the night departure.

For many masculine nouns in Bokmål:

• en avgang = a departure
• avgangen = the departure

When avgang becomes part of the compound nattavgang, it still takes the definite ending in the same way:

• en nattavgang = a night departure
• nattavgangen = the night departure

So the definite article is usually attached to the end of the noun instead of being a separate word like English the.

Because Norwegian usually does not add den before a definite noun unless there is a special reason.

Normally you say:

• nattavgangen = the night departure

You would use den if you wanted extra emphasis or if there were an adjective:

• den sene nattavgangen = the late night departure

This pattern is often called double definiteness when an adjective is present:

• den
  • adjective + noun with definite ending

But with just the noun by itself, nattavgangen is enough.

Begynner is the present tense of begynne = to begin / to start.

So:

• å begynne = to begin
• begynner = begins / is beginning / starts

In this sentence, it means something like begins or starts.

Examples:

• Timen begynner klokka åtte. = The class starts at eight.
• Filmen begynner snart. = The film begins soon.

It can mean either, depending on context. In many cases, English begin and start both fit.

So in this sentence, begynner could be understood as:

• begins
• starts

Norwegian begynne is a very common general verb for this idea.

Here, ved means something like:

• at
• by
• near

So ved fergeterminalen means that the starting point is at/by the ferry terminal.

The exact English translation depends on context, but the basic idea is location close to or at a place.

Because ved often emphasizes location by or at a place, especially as a point or area.

• ved fergeterminalen = by / at the ferry terminal

Using på would usually suggest being on or at something in a different way, and it may sound less natural here depending on the exact context.

Prepositions do not always match English one-to-one, so this is something learners often just have to get used to through exposure.

A useful rule of thumb:

• ved = at/by/near
• på = on, onto, or at certain places/events depending on idiom

It is another compound noun:

• ferge = ferry
• terminal = terminal
• -en = the definite ending

So:

• fergeterminal = ferry terminal
• fergeterminalen = the ferry terminal

Again, Norwegian prefers to combine the noun parts into one word.

Yes. This is very standard word order:

• Nattavgangen = subject
• begynner = verb
• ved fergeterminalen = place expression

So the structure is basically:

Subject + Verb + Place

That is very common in main clauses.

Yes. Norwegian main clauses follow the V2 rule, which means the finite verb usually stays in the second position.

Original sentence:

• Nattavgangen begynner ved fergeterminalen.

If you move the place expression to the front, the verb still stays second:

• Ved fergeterminalen begynner nattavgangen.

That sounds a bit more marked or literary in this case, but it is grammatical.

So unlike English, if something other than the subject comes first, Norwegian usually puts the verb before the subject.

Both avgang and terminal are commonly treated as masculine in Bokmål, which is why you see the definite ending -en.

Examples:

• en avgang → avgangen
• en terminal → terminalen

Then in compounds:

• en nattavgang → nattavgangen
• en fergeterminal → fergeterminalen

You would remove the definite endings:

• En nattavgang begynner ved en fergeterminal.

But that sounds more general and less natural in many real-life contexts.

More likely:

• En nattavgang begynner ved fergeterminalen. = A night departure starts at the ferry terminal.
• Nattavgangen begynner ved fergeterminalen. = The night departure starts at the ferry terminal.

So the original sentence sounds like it refers to a specific, known departure.

Yes. It is very typical Norwegian word-building.

Norwegian often creates precise meanings by combining nouns:

• togavgang = train departure
• kveldsavgang = evening departure
• morgenavgang = morning departure
• nattavgang = night departure

This is a very productive pattern, and learning to recognize compounds will help a lot with reading Norwegian.