İtiraz mercii belge numarasını istedi.

It is a formal legal/administrative phrase meaning something like the appeal authority, the objection authority, or the office/body that handles appeals or objections.

In this sentence, itiraz mercii is the subject: it is the one that requested something.

• itiraz = objection, appeal
• mercii = authority, competent office/body

So the phrase refers to the institution or authority dealing with the objection/appeal.

It is a noun here.

• itiraz = objection / appeal
• itiraz etmek = to object / to appeal

In itiraz mercii, the word itiraz is not acting as a verb. It is the first part of a noun phrase, modifying mercii.

This is the standard written form used in official expressions such as başvuru mercii and itiraz mercii.

For a learner, the safest approach is to treat itiraz mercii as a fixed bureaucratic/legal term and memorize it as a whole. It can look a little irregular compared with more everyday noun patterns, so it is normal to pause at it.

Because Turkish commonly forms this kind of phrase with a noun compound.

Pattern:

• belge = document
• numara = number
• belge numarası = document number

In this pattern, the second noun usually takes the ending -(s)I. That is why numara becomes numarası.

This is very common in Turkish:

• telefon numarası = telephone number
• kimlik kartı = identity card
• öğrenci belgesi = student document/certificate

So belge numarası is the normal Turkish way to say document number.

Because it is the definite direct object of the verb.

The base phrase is:

• belge numarası = document number

In the sentence, the authority requested the specific document number, so Turkish adds the accusative ending.

That gives:

• belge numarası
  • accusative
• belge numarasını

The n appears because Turkish often uses a buffer n after this kind of possessed/compound form before adding another ending.

So:

• numarası = its/document number
• numarasını = the document number, as a specific object

Grammatically, istedi comes from istemek, which often means to want.

But in many real sentences, especially formal or administrative ones, istemek can also mean to ask for or to request.

So in this sentence, the most natural English meaning is:

• requested
• or asked for

Also, istedi is:

• simple past tense
• third person singular

So literally it is wanted / requested.

Because Turkish does not have a direct equivalent of the English article the.

Instead, definiteness is often shown by:

• context
• word order
• case marking

Here, belge numarasını has the accusative ending, which strongly suggests a specific object. That is one reason English usually translates it with the:

• the document number

If you removed that accusative ending, the phrase would sound less definite and could be understood more like a document number or some document number, depending on context.

The neutral Turkish word order here is:

• Subject + Object + Verb

So:

• İtiraz mercii = subject
• belge numarasını = object
• istedi = verb

This is very typical Turkish sentence structure.

English usually prefers Subject + Verb + Object, but Turkish often puts the verb at the end.

Yes, Turkish word order is flexible, but changing it usually changes the focus or emphasis, not the core meaning.

The sentence as given is the most neutral version:

• İtiraz mercii belge numarasını istedi.

A different order such as:

• Belge numarasını itiraz mercii istedi.

can put more emphasis on belge numarasını.

So the endings help show grammatical function, while word order often helps show what is being highlighted.