Το βιβλιοπωλείο είναι απέναντι από το πανεπιστήμιο.

Greek often combines elements into a single compound word.

βιβλιοπωλείο means bookstore / bookshop, and it is built from parts related to book and selling. Greek does this very naturally, so a word that might feel like two pieces in English is often written as one word in Greek.

Because both βιβλιοπωλείο and πανεπιστήμιο are neuter singular nouns.

In Greek, nouns have grammatical gender, and the article must agree with the noun:

• το βιβλιοπωλείο
• το πανεπιστήμιο

So το here is the neuter singular form of the.

είναι means is.

This sentence is an A is B / A is somewhere type of sentence, so Greek uses είναι just as English uses is:

• Το βιβλιοπωλείο είναι... = The bookstore is...

Greek often drops subject pronouns like I, you, he, but it does not normally drop είναι in a sentence like this.

Yes, από very often means from, but here it is part of the fixed expression απέναντι από, which means opposite / across from.

So you should learn απέναντι από as a unit:

• απέναντι από το πανεπιστήμιο = opposite / across from the university

On its own, απέναντι can sometimes mean opposite or across, but when you say what something is opposite from, Greek normally uses απέναντι από + noun.

After από, Greek uses the accusative case.

So grammatically, το πανεπιστήμιο here is accusative. The reason it looks unchanged is that for many neuter singular nouns, the nominative and accusative forms are identical.

So:

• nominative: το πανεπιστήμιο
• accusative: το πανεπιστήμιο

Same form, different function.

A rough English-friendly guide:

• βιβλιοπωλείο ≈ vee-vlee-o-po-LEE-o
• πανεπιστήμιο ≈ pa-ne-pi-STEE-mi-o
• είναι ≈ EE-ne
• απέναντι ≈ a-PE-na-di

The accent mark shows which syllable is stressed:

• βιβλιοπωλείο
• πανεπιστήμιο
• απέναντι
• είναι

Also, remember that Greek β is pronounced like English v, not b.

No, Greek word order is fairly flexible.

The given version is a very natural, neutral way to say it:

• Το βιβλιοπωλείο είναι απέναντι από το πανεπιστήμιο.

But Greek can move things around for emphasis. For example:

• Απέναντι από το πανεπιστήμιο είναι το βιβλιοπωλείο.

That still means the same thing, but it puts more focus on the location.

Usually, yes.

Greek uses the definite article very often with specific places and buildings, even in cases where English might sometimes sound less article-heavy. In this sentence, both places are specific:

• το βιβλιοπωλείο
• το πανεπιστήμιο

So using the articles is the normal, natural choice.

It can match either one in English, depending on context.

For buildings and locations, English often says across from, while opposite is also correct. So this Greek phrase can be translated naturally either way:

• The bookstore is opposite the university.
• The bookstore is across from the university.

For the negative, put δεν before the verb:

• Το βιβλιοπωλείο δεν είναι απέναντι από το πανεπιστήμιο.
• The bookstore is not opposite / across from the university.

For a yes-no question, Greek often keeps the same word order and relies on intonation in speech. In writing, Greek uses ; as the question mark:

• Το βιβλιοπωλείο είναι απέναντι από το πανεπιστήμιο;

So be careful: in Greek, ; means ?.