Masa her akşam siliniyor.

Because masa is the subject of this sentence, not the direct object.

In the active version, you could say:

• Biri masayı her akşam siliyor. = Someone wipes the table every evening.

There, masayı is the direct object, so it takes the accusative ending -yı.

But in the passive:

• Masa her akşam siliniyor.

the thing affected by the action becomes the grammatical subject, so it appears as plain masa, not masayı.

Her akşam means every evening.

• her = every
• akşam = evening

So:

• her gün = every day
• her hafta = every week
• her akşam = every evening

This is a very common pattern in Turkish: her + singular noun.

After her meaning every, Turkish normally uses the noun in the singular bare form.

So you say:

• her gün
• her sabah
• her akşam
• her yıl

not plural forms like her akşamlar.

And akşamı would not fit here either, because that ending would suggest a different grammatical role. In this sentence, akşam is just part of the time expression her akşam = every evening.

Siliniyor can be broken down like this:

• sil- = wipe / clean by wiping
• -in- = passive marker here
• -iyor = present continuous / ongoing present

So siliniyor literally means something like:

• is being wiped
• is wiped
• gets wiped

depending on context.

In this sentence, it expresses a repeated action: The table gets wiped every evening.

Turkish uses the passive when the doer is unknown, unimportant, or simply not mentioned.

So:

• Biri masayı her akşam siliyor. = Someone wipes the table every evening.
• Masa her akşam siliniyor. = The table is wiped every evening.

The passive is very natural if the speaker wants to focus on the table rather than on who wipes it.

It can do both, depending on context.

With her akşam present, the sentence is understood as a habitual/repeated action:

• Masa her akşam siliniyor. = The table is wiped every evening.

Even though -iyor is often taught first as the present continuous, Turkish also uses it a lot for regular actions when the context makes that clear.

So here it does not mean the table is being wiped at this exact moment every evening in some strange continuous way. It simply means this happens regularly.

Yes, Masa her akşam silinir is also possible.

Very roughly:

• siliniyor sounds more like a real ongoing practice or current routine
• silinir sounds more general, neutral, or sometimes more formal

Both can translate as The table is wiped every evening.

Learners often expect a strict English-style difference, but in Turkish the choice is often about style and nuance rather than a big change in meaning.

Turkish has no separate word like English the.

So masa can mean:

• table
• the table
• sometimes even a table

depending on context.

In this sentence, English usually translates it as the table because the situation suggests a specific table:

• Masa her akşam siliniyor. = The table is wiped every evening.

The word order here is very natural:

• Masa = subject/topic
• her akşam = time expression
• siliniyor = verb

So the structure is roughly:

Subject + time expression + verb

Turkish often puts the verb at the end.

You could also move things around for emphasis, for example:

• Her akşam masa siliniyor.

This still means the same thing, but the emphasis may shift slightly toward every evening.

Yes, but once you mention the doer, Turkish often either uses an active sentence or adds an agent phrase.

For example:

• Görevli masayı her akşam siliyor. = The attendant wipes the table every evening.
• Masa her akşam görevli tarafından siliniyor. = The table is wiped by the attendant every evening.

The passive version with tarafından is possible, but in everyday Turkish the active sentence is often more natural if the doer matters.

In this sentence, yes, it is passive.

The base verb is:

• silmek = to wipe

The passive form is:

• silinmek = to be wiped

So:

• Masa siliniyor. = The table is being wiped / gets wiped.

Some Turkish verb forms can have more than one function in different contexts, but here the meaning is clearly passive.

A simple active version would be:

• Biri masayı her akşam siliyor. = Someone wipes the table every evening.

Or with a specific subject:

• Ayşe masayı her akşam siliyor. = Ayşe wipes the table every evening.

Comparing them helps:

• Masa her akşam siliniyor. = focus on the table / passive
• Ayşe masayı her akşam siliyor. = focus on who does it / active