Στο σαλόνι έχουμε έναν γαλάζιο τοίχο δίπλα στο παράθυρο.

Στο means in the or to the, depending on context.

It is a contraction of:

• σε = in, at, to
• το = the (neuter singular)

So:

• σε + το → στο

In this sentence, Στο σαλόνι means in the living room.

Σαλόνι means living room, sitting room, or lounge.

It is a neuter noun, which is why it goes with το:

• το σαλόνι = the living room

In the sentence, Στο σαλόνι is a location phrase: in the living room.

Έχουμε is the 1st person plural form of έχω = to have.

So:

• έχω = I have
• έχουμε = we have

In this sentence, έχουμε is being used in a very natural Greek way to describe what a room contains:

• Στο σαλόνι έχουμε... = In the living room, we have...

In English, you might also say There is... in the living room, but Greek often uses we have in this kind of descriptive context.

Because τοίχο is the direct object of έχουμε.

The basic dictionary form is:

• ο τοίχος = the wall

But after a verb like έχουμε (we have), the noun goes into the accusative case:

• έναν τοίχο = a wall

The adjective must also match the noun in gender, number, and case, so:

• ένας γαλάζιος τοίχος = a light blue wall (nominative)
• έναν γαλάζιο τοίχο = a light blue wall (accusative)

So the endings change because Greek marks grammatical function.

This is the normal accusative singular form of a masculine noun ending in -ος.

Pattern:

• ο τοίχος = the wall (nominative)
• τον τοίχο = the wall (accusative)

Without the definite article:

• ένας τοίχος = a wall
• έναν τοίχο = a wall

So in the sentence, τοίχο is correct because it is the object of έχουμε.

Yes, έναν here is the indefinite article meaning a.

Greek does have an indefinite article, unlike some other languages. Its form changes by gender and case.

For masculine singular:

• ένας = a (nominative)
• έναν = a (accusative)

So:

• ένας τοίχος = a wall
• έναν τοίχο = a wall (as object)

English a/an does not change form, but Greek does.

Γαλάζιο means light blue, sky blue, or azure, not just any blue.

Greek often distinguishes between:

• μπλε = blue
• γαλάζιος / γαλάζια / γαλάζιο = light blue, sky blue

So:

• έναν γαλάζιο τοίχο = a light blue wall

Also, γαλάζιο changes form to agree with τοίχο:

• masculine accusative singular: γαλάζιο

That is the normal position for an adjective in Greek:

• article + adjective + noun
• or indefinite article + adjective + noun

So:

• έναν γαλάζιο τοίχο

This is exactly like a light blue wall in English.

Greek adjectives can sometimes appear in other positions, but here this is the standard and most natural order.

It means next to the window or beside the window.

Breakdown:

• δίπλα = next to / beside
• στο παράθυρο = the window

Together:

• δίπλα στο παράθυρο = next to the window

It tells you where the wall is located relative to the window.

Again, στο is σε + το.

• το παράθυρο = the window
• σε το παράθυρο → στο παράθυρο

After δίπλα, Greek commonly uses σε to mean next to something:

• δίπλα στο παράθυρο = next to the window

Also, παράθυρο is a neuter noun, so the article is το.

Because for many neuter nouns, the nominative and accusative singular are the same.

So:

• το παράθυρο = the window (nominative)
• το παράθυρο = the window (accusative)

That is why you do not see a visible change, unlike with τοίχος → τοίχο.

Yes. Greek word order is more flexible than English, because case endings show grammatical roles.

The sentence as given:

• Στο σαλόνι έχουμε έναν γαλάζιο τοίχο δίπλα στο παράθυρο.

This puts emphasis first on the location: In the living room...

You could also hear things like:

• Έχουμε έναν γαλάζιο τοίχο στο σαλόνι, δίπλα στο παράθυρο.
• Έναν γαλάζιο τοίχο έχουμε στο σαλόνι, δίπλα στο παράθυρο.

These are not identical in emphasis, but they are all understandable. The original sentence is very natural.

Both can be natural, but they are slightly different in style.

• Στο σαλόνι έχουμε έναν γαλάζιο τοίχο... = In the living room, we have a light blue wall...
• Στο σαλόνι υπάρχει ένας γαλάζιος τοίχος... = In the living room, there is a light blue wall...

The version with έχουμε sounds very natural when someone is describing features of a house, room, or space from the point of view of the people who own or use it.

The version with υπάρχει is more neutral and simply states existence.

A useful way to group the sentence is like this:

• Στο σαλόνι = location phrase
• έχουμε = verb
• έναν γαλάζιο τοίχο = direct object
• δίπλα στο παράθυρο = location phrase modifying τοίχο

Inside έναν γαλάζιο τοίχο, all three words go together and match:

• έναν = masculine accusative singular
• γαλάζιο = masculine accusative singular
• τοίχο = masculine accusative singular

That agreement is one of the main things Greek learners need to notice.