Der Eingang ist barrierefrei; wir halten ihn frei.

Because Eingang is a masculine noun in German. Its dictionary form is der Eingang.

In this sentence, der Eingang is also the subject, so it stays in the nominative case:

• der Eingang = the entrance

This is why the sentence begins with Der Eingang ist ...

Here, barrierefrei is a predicate adjective. It comes after ist and describes the subject der Eingang.

So the structure is:

• Der Eingang = subject
• ist = verb
• barrierefrei = adjective describing the subject

Because it comes after sein (to be), it does not take an adjective ending.

Compare:

• Der Eingang ist barrierefrei.
  → predicate adjective, no ending
• ein barrierefreier Eingang
  → adjective before a noun, so it does take an ending

Because it is not directly in front of a noun here.

German adjectives behave differently depending on position:

1. Before a noun → they take endings

   • ein barrierefreier Eingang

2. After verbs like sein, werden, bleiben → they usually do not take endings

   • Der Eingang ist barrierefrei.

So in this sentence, barrierefrei stays in its basic form.

This is a very common German pattern:

• jemanden / etwas frei halten

It means to keep someone/something clear, open, unobstructed, available, or free depending on context.

In this sentence:

• wir = subject
• halten = verb
• ihn = direct object
• frei = adjective describing the state we keep it in

So grammatically, frei is not an adverb here. It is more like an object complement: we keep it free/clear.

A close English parallel is:

• We keep it clear.
• We keep it unobstructed.

Because ihn is the accusative form of the masculine pronoun er.

The noun Eingang is masculine:

• nominative: der Eingang
• accusative: den Eingang

When replaced by a pronoun:

• nominative: er
• accusative: ihn

In wir halten ihn frei, ihn is the direct object of halten, so accusative is required.

Because German pronouns normally follow the grammatical gender of the noun, not natural logic.

Since Eingang is masculine (der Eingang), the matching pronoun is:

• er in nominative
• ihn in accusative

So even though English would use it, German uses the masculine forms because Eingang is grammatically masculine.

They are related, but they do not mean the same thing here.

• barrierefrei = accessible, barrier-free
  This means the entrance is designed so people can use it without barriers, for example wheelchair users.

• frei in wir halten ihn frei = clear, unobstructed
  This means people make sure nothing blocks the entrance.

So the sentence is saying two different things:

1. the entrance is accessible
2. they keep it clear

It is better understood as a verb + adjective construction rather than a normal separable-prefix verb like aufstehen.

In practice, though, it can look similar:

• Wir halten den Eingang frei.
• Haltet bitte den Eingang frei.
• Wir haben den Eingang freigehalten.

The past participle freigehalten can make it feel like a separable verb, but for learners it is often most useful to remember the whole expression:

• etwas frei halten = to keep something clear/free

The semicolon connects two closely related independent clauses:

• Der Eingang ist barrierefrei
• wir halten ihn frei

Each clause could stand on its own as a sentence, but the semicolon shows a strong connection between them.

You could also write:

• Der Eingang ist barrierefrei. Wir halten ihn frei.
• Der Eingang ist barrierefrei, und wir halten ihn frei.

The semicolon is just a stylistic punctuation choice.

Yes, absolutely.

Both are correct:

• Wir halten den Eingang frei.
• Wir halten ihn frei.

Using ihn avoids repeating den Eingang and sounds natural if the noun has just been mentioned.

This is very common in German, just as in English:

• The entrance is accessible; we keep it clear.

Yes. It is built from:

• Barriere = barrier
• frei = free

So literally it means free of barriers.

German forms many adjectives this way, for example:

• alkoholfrei = alcohol-free
• kostenfrei = free of charge
• schmerzfrei = pain-free

So barrierefrei is a very typical German adjective formation.

Yes, frei is a very flexible adjective. It can mean things like:

• free
• available
• vacant
• clear
• unrestricted

The exact meaning depends on context.

Here, because it is used with halten and an entrance, frei halten means:

• keep clear
• keep unobstructed

So you should understand frei here from the whole expression, not as an isolated word.