Noun Completion

İsım Tamlananları - There are Four Forms of Noun Completion

A noun may take another one or more nouns as describing nouns in order to make its basic meaning clear. These noun groups are called Compound Nouns. The describing nouns are called Completing Nouns - isim tamlayan (belirten) - and the Noun itself is called a Completed Noun - isim tamlanan (belirtilen).

(1) - Descriptive Noun Completion - Belirtili isim tamlaması

Here the Describing (Completing) Noun shows who or what is owned by the Described (Completed) Noun.
Describing Noun (Tamlayan isim) : is suffixed with -in, -ın, -ün, -un
Described Noun (Tamlanan isim) : is suffixed with the third person singular -i, -ı, -ü, -u

Konağıin bahçesi - The garden of the mansion, The mansion's garden - Shows that - "the garden belongs to the mansion". -un - Describing Noun Suffix, -i - Described noun Suffix, -s - Buffer Letter to keep vowels apart.
Çantanın fermuarı - The zip of the bag, The bag's zip - Shows that - "the zip belongs to (is part of) the bag". -ın - Describing Noun Suffix, -ı - Described Noun Suffix, -n - Buffer Letter to keep vowels apart.
Bankanın kapısı - The door of the bank, The bank's door - shows that - "the door is part of and belongs to the bank". -ın - Describing Noun Suffix, -ı - Described Noun Suffix, -n, -s - Buffer Letters to keep vowels apart.
Kavanozun kapağı - The lid of the jar, The jar's lid - shows that - "the lid belongs to the jar". -un - Describing Noun Suffix, -ı - Described Noun Suffix, ğ - Softened Consonant from -k on addition of vowel suffix

A Special case - su (water)
The only noun in Turkish which does not conform to Buffer Letter rules is Su - water. Whether as a Describing (Completing) Noun or as a Described (Completed) Noun will take the Buffer letter -y- instead of the normal -s-. This may be for avoiding the ugly - "susu".
Suyun sesi - The sound of the water, The water's sound - shows that - "the sound comes from the water".
-un - Describing Noun Suffix, -i - Described Noun Suffix, -y - Buffer Letter to keep vowels apart.
Elmanın suyu - The apple's juice , The juice of the apple - shows that - "the juice (water) belongs to the apple".
-ın - Describing Noun Suffix, -u - tamlanan eki, -y - kaynaştırma harfi

Summary of Noun Completion Suffixes

1. The Describing Noun suffixes are always -in, -ın, -ün, -un -(Vowel harmony applies)
2. The Described Noun suffixes are always -i, -ı, -ü, -u - (Vowel harmony applies).
3. Describing Nouns which end in a vowel always use buffer letter -n- where required.
4. Described Nouns which end in a vowel always use buffer letter -s- where required.
5. The single exception su - water which takes buffer letter -y- as both a Describing or Described Noun.

(2) - Non-Descriptive Noun Completion - Belirtisiz isim tamlaması

Only the Completed Noun takes the suffix of the third person singular -i, -ı, -ü, -u . Described Nouns which end in a vowel always use buffer letter -s- where required.
Yaz mevsimi - summer season -i - Completed Noun Suffix
Kış tatili - winter holiday -u - Completed Noun Suffix
Yolcu gemisi - ferryboat [Lit: traveller boat] -i - Completed Noun Suffix (s - buffer letter for the third person singular.)
Armut ağacı - pear tree -ı - Completed Noun Suffix - (c - Softened Consonant)

(3) - Unrelated Noun Completion - Takısız isim tamlaması

In this compound neither Completing or Completed Noun take a suffix. This Compound noun is used for description of the material from which it is made:
Plastik sandalye - plastic chair
pamuk mendil - cotton handkerchief
tahta masa - wooden table
demir köprü; - iron bridge
cam bardak - glass tumbler
benzin depo - petrol dump

(4) - Chained Noun Completion - Zincirleme isim tamlaması

More than two nouns can be chained together to produce a Compound Noun
incir ağacının yaprağı - the fig tree leaf
paslanmaz çelik çaydanlığın kapağı - the stainless steel teapot's lid
derginin kapağının resimleri - the pictures of the magazine cover
İngiliz consuloluğun kapısı - the door of the English Consulate
Manisa Trafik Polis karakolu - Manisa Traffic Police headquarters
yolcu gemisinin güvertesi - the deck of the ferry boat

Compound Nouns can be plural

Portakal bahçeleri - Orange orchards
öğretmenler toplantısı - Teachers Meeting
çocukların defterleri- Children's notebooks
evlerin kapılarının zilleri - house door bells

Compound Nouns can take Suffixes of Condition

Kiraz bahçeleri - the cherry orchards - [subject.]
Elma bahçelerini - the apple orchards - [object.]
Portakal bahçelerine - to the orange orchards
Sebze bostanlarında - in the vegetable gardens
Belediye parklarından - from the municipal parks
Described Nouns which end in a vowel always use buffer letter -n- where required.

Personal Name Compound Nouns

If a Personal noun consists of more than one title, it is still counted as a single noun.
Mustafa Kemal Paşa Bulvarı - Mustafa Kemal Paşa Avenue - Indefinite compound noun
Mustafa Kemal Paşa - Describing Noun
Bulvarı - Described Noun