Üst kattaki oda daha aydınlık görünüyor.

Üst kattaki means the one on the upper floor / upstairs.

It breaks down like this:

• üst = upper, top
• kat = floor, storey
• katta = on the floor / on that storey
  
  • this is kat
    • the locative ending -da/-de/-ta/-te
• -ki = a suffix that turns a location phrase into something like the one that is in/on...

So:

• üst katta = on the upper floor
• üst kattaki oda = the room that is on the upper floor

In natural English, you would usually just say the upstairs room or the room on the upper floor.

Because in Turkish, modifiers normally come before the noun they describe.

So:

• üst kattaki oda = the room on the upper floor
• literally: upper floor-on-the room

This is very normal Turkish word order. The descriptive part comes first, and the noun being described comes last.

Compare:

• büyük ev = big house
• bahçedeki çocuk = the child in the garden
• üst kattaki oda = the room upstairs

Here, -ki attaches to a location expression and creates an adjective-like form.

So:

• üst katta = on the upper floor
• üst kattaki = the one that is on the upper floor / the one upstairs

Then it modifies oda:

• üst kattaki oda = the room that is on the upper floor

This -ki is very common in Turkish:

• masadaki kitap = the book on the table
• dolaptaki tabaklar = the plates in the cupboard
• okuldaki öğrenciler = the students at school

A useful way to think of it is:

• location + -ki = the one(s) in/on/at that location

Because the base is katta + -ki, not katda + -ki.

The locative ending is chosen by consonant harmony:

• after a voiceless consonant like t, Turkish uses -ta/-te
• kat ends in t
• so kat + ta = katta

Then:

• katta + ki = kattaki

So the form is perfectly regular.

Daha means more.

So:

• aydınlık = bright
• daha aydınlık = brighter / more bright

In this sentence, daha aydınlık görünüyor means looks brighter.

Turkish usually forms the comparative with daha + adjective:

• daha büyük = bigger
• daha güzel = more beautiful / prettier
• daha sessiz = quieter

Because Turkish does not always need to state the comparison explicitly.

Daha aydınlık already tells you that something is being compared with something else, even if that other thing is understood from context.

So this sentence can mean:

• The room upstairs looks brighter.

The listener may already know what it is brighter than:

• than the downstairs room
• than the other room
• than before

If Turkish wants to state the comparison clearly, it can do so:

• Alt kattaki odadan daha aydınlık görünüyor.
• It looks brighter than the room downstairs.

Here -dan/-den gives the meaning of than.

Because aydınlık is the more natural word for bright / well-lit when talking about a room or space.

• aydınlık oda = a bright room
• karanlık oda = a dark room

Aydın can mean things like:

• enlightened
• educated
• intellectual

So for physical brightness in a room, aydınlık is the safer and more common choice.

Görünüyor means it looks / it seems / it appears.

It comes from the verb görünmek, which means:

• to appear
• to be visible
• to seem

So:

• aydınlık görünüyor = it looks bright
• daha aydınlık görünüyor = it looks brighter

In this sentence, it is not necessarily saying the room truly is brighter in some measured way. It is describing how it appears to the speaker.

It is built from:

• görün- = appear / seem / be visible
• -üyor = present continuous tense ending
• implied o = he/she/it

So:

• görünüyor = it is appearing / it appears / it looks

In natural English, the best translation is usually looks or seems, not is appearing.

Because Turkish normally puts the finite verb at the end of the sentence.

So the structure here is:

• Üst kattaki oda = subject
• daha aydınlık = complement
• görünüyor = verb

This verb-final pattern is very typical in Turkish.

A very literal gloss would be:

• The upstairs room brighter looks.

Of course, natural English changes the order:

• The room upstairs looks brighter.

Because Turkish does not have definite articles like English the.

So oda can mean:

• a room
• the room

The exact meaning depends on context.

In this sentence, üst kattaki oda is naturally understood as the room on the upper floor, because it refers to a specific room already identifiable from the description.

Because oda is the subject of the sentence, and subjects are normally in the basic form, often called the nominative.

So:

• oda = room
• no extra ending is needed here

If it had another role, it might take a case ending:

• odayı = the room (object)
• odada = in the room
• odadan = from the room

But here it is simply the thing that looks brighter, so plain oda is correct.

Yes. That is a very good translation.

Görünüyor often overlaps with English expressions like:

• looks
• seems
• appears

So depending on context, all of these may work:

• The room upstairs looks brighter.
• The upstairs room looks brighter.
• The upstairs room seems brighter.

The nuance is about appearance, not a hard fact established by measurement.

Yes, but the neutral and most natural order is:

• Üst kattaki oda daha aydınlık görünüyor.

Turkish can move parts around for emphasis, but the verb usually stays at the end.

For example, you might hear:

• Daha aydınlık görünüyor üst kattaki oda.

This can sound more marked or emphatic, like:

• It’s the upstairs room that looks brighter.

So learners should treat the original version as the standard pattern.

Often, yes.

Üst kat literally means upper floor or upper storey. Depending on context, English may translate it as:

• upper floor
• upstairs
• the floor above

So:

• üst kattaki oda can be translated as:
  • the room on the upper floor
  • the upstairs room
  • the room upstairs

All are possible, depending on what sounds most natural in English.