Das Bibliothekskonto zeigt den Rückgabetermin.

German often combines nouns into a single compound noun. So Bibliothekskonto is made from:

• Bibliothek = library
• Konto = account

Together, Bibliothekskonto means library account.

This is very normal in German. English often uses separate words, but German usually joins them:

• library card → Bibliotheksausweis
• return date → Rückgabetermin

That -s- is a common linking sound in German compounds. It is often called a linking s or Fugen-s.

So:

• Bibliothek
  • Konto
• becomes Bibliothekskonto

You cannot always predict perfectly when German uses this linking -s-, so it is often best to learn compounds as whole words. It does not mean possession in the English sense of library's account. It is just part of how the compound is formed.

The article is das because Konto is a neuter noun: das Konto.

In German compound nouns, the last noun decides the gender of the whole word. Since the last part is Konto, the whole compound is also neuter:

• das Konto
• das Bibliothekskonto

Because Rückgabetermin is the direct object of the verb zeigt.

The sentence structure is:

• Das Bibliothekskonto = the subject
• zeigt = the verb
• den Rückgabetermin = the direct object

Rückgabetermin is a masculine noun, so:

• nominative: der Rückgabetermin
• accusative: den Rückgabetermin

Since it is the direct object here, German uses the accusative case:

• den Rückgabetermin

The final part of the compound is Termin, and Termin is masculine: der Termin.

Again, in German compounds, the last element controls the gender. So:

• der Termin
• der Rückgabetermin

That is why the accusative form becomes den Rückgabetermin.

• das Bibliothekskonto is nominative, because it is the subject of the sentence.
• den Rückgabetermin is accusative, because it is the direct object.

So the basic pattern is:

• Subject (nominative)
  • verb
    • direct object (accusative)

Here:

• Das Bibliothekskonto = nominative
• zeigt = verb
• den Rückgabetermin = accusative

The infinitive is zeigen = to show.

Here it is conjugated for third-person singular, because the subject das Bibliothekskonto is singular:

• ich zeige
• du zeigst
• er/sie/es zeigt
• wir zeigen
• ihr zeigt
• sie/Sie zeigen

Since das Bibliothekskonto is like it, German uses:

• es zeigt
• therefore: Das Bibliothekskonto zeigt ...

In a normal German main clause, the finite verb usually comes in second position.

So:

• Das Bibliothekskonto = position 1
• zeigt = position 2
• den Rückgabetermin = the rest of the sentence

This is one of the most important German word-order rules.

Yes, German allows some flexibility, but the finite verb still stays in second position in a main clause.

For example, you could say:

• Den Rückgabetermin zeigt das Bibliothekskonto.

This is grammatically possible, but it sounds more marked or emphasizes den Rückgabetermin. The original sentence is the most neutral and natural version for most contexts:

• Das Bibliothekskonto zeigt den Rückgabetermin.

In German, all nouns are capitalized. That is why you see:

• Bibliothekskonto
• Rückgabetermin

This is a standard spelling rule in German, not special emphasis.

Rückgabetermin is also a compound noun:

• Rückgabe = return
• Termin = appointment/date/scheduled time

Together it means the due date or return date.

As with Bibliothekskonto, the last part determines the gender:

• der Termin
• so: der Rückgabetermin

Yes, zeigt is perfectly natural here. It means something like shows or displays.

Depending on context, German might also use verbs like:

• nennt = states
• enthält = contains
• gibt ... an = indicates

But in a sentence about what appears on a library account page or screen, zeigt is very common and idiomatic.

It is useful as a pattern:

• Das/Der/Die [subject] zeigt den/die/das [object].

For example:

• Die App zeigt den Kontostand.
• Das System zeigt die Gebühr.
• Der Bildschirm zeigt das Datum.

So this sentence is a good model for:

1. subject in nominative,
2. verb in second position,
3. direct object in accusative.