The Possessive Relationship

All about Possession
There is a special construction in Turkish which means - belonging to.... In English generally only the Possessor is marked as in - Janet's house - where the 's tells us that the house belongs to Janet. However, possession can also be marked by both the Possessor and the Possessed in English as in - the hair of the dog ..... In this case both words - hair - and - dog - are marked THE hair and OF THE dog.
This then is the way that Turkish uses, for both words, the Possessor and the Possessed are always marked viz: köpeğin tüyü (Köpeğ-in tüy-ü) - The hair of the dog [Lit: dog-the-of hair-the]

The Possessor

In Turkish the possessor is suffixed with -in, -ın, -un, -ün, or -nin -etc. when suffixed to a word which ends in a vowel. The -in suffix means - of, belonging to.. - in English, and of course is subject to vowel harmony. In grammar this is called the Genitive Case

Formation of the Possessor:

For words ending in a consonant we add -in, -ın, -un, -ün - according to Vowel Harmony Rules..
adamın - (adam-ın) - the man's
adam - man - adamın - of the man, the man's
göz - eye - gözün - of the eye, the eye's

All plural forms end in a consonant -ler/-lar.
Example: adamların - (adam-lar-ın) - of the men.
adamlar - the men - adamların - of the men, the men's
fareler - the mice - farelerin - of the mice, the mice's
lastikler - the tyres - lastiklerin - of the tyres, the tyres'

Nouns ending in vowels use buffer letter -n to form -nin.
Example: banyonun - (banyo-nun) - of the bath.
banyo - bath - banyonun - of the bath, the bath's
köprü - bridge - köprünün - of the bridge, the bridge's

Formation of the Possessed

The possessed item in Turkish is suffixed with -i, -ı, -u, -ü - his, hers, its.
If the word being suffixed already ends in a vowel then the buffer letter -s- is used after this final vowel, thus the forms -si, -sı, -su, -sü are used. This suffix is also is subject to vowel harmony as shown above.

Formation of the Possessive Relationship

Both the Possessor and Possessed are suffixed in Turkish as follows:
The Possessor - adam - man with the Possessed - el - hand becomes:
adamın eli - [adam-ın el-i] - the man's hand, the hand of the man - (Lit: man-of hand-his.)
The Possessor - Mehmet - Mehmet - with the Possessed - palto - overcoat - becomes:
Mehmet 'in paltosu - [Mehmet-'in palto-su] - Mehmet's overcoat - (Lit: Mehmet-of overcoat-his)

When adding suffixes to Proper names that the suffix is separated by an apostrophe. The easy way to remember is that any noun beginning with a capital letter should be separated from its suffix. i.e. Londra - (London) - becomes - Londra'nın - London's, of London.

The Plurals of the Possessive Relationship
The plurals are formed by the addition of -ler or -lar to either the possessor or the possessed or to both according to context. The following examples should make this clear:

Both Possessor and Possessed Singular
adamın arabası - [adam-ın araba-sı] - the man's car
evin damı - [ev-in dam-ı] - the roof of the house

The Possessor Plural and Possessed Singular
yıldızların ışığı - [yıldız -lar-ın ışığ-ı] - the light of the stars
adamların arabası - [adam-lar-ın araba-sı] - the men's car

The Possessor Singular and Possessed Plural
adamın arabaları - [adam-ın araba-lar-ı] - the man's cars
odanın duvarları - [oda-nı duvar-lar-ı] - the walls of the room

Both Possessor Plural and Possessed Plural
adamların arabaları - [adam-lar-ın araba-lar-ı] - the men's cars
çocukların oyunları - [çocouk-lar-ın oyun-lar-ı] - the children's games

The Possessive Relationship in Use
The Possessive Relationship is Compound Noun in its own right and as such can have further suffixes such as -dan, -den - from, -da -de - in, on at , -a , -e - to, towards etc. - added to the Possessed item(s) to modify the meaning according to context:
Adamın arkadaşına kitabı verdim - I gave the book to the man's friend
Adam-ın arkadaş-ı-na kitabı verdim - [Lit: Man-of friend-his-to book-the gave-I]
Adamın arkadaşından kitabı aldım - I took the book from the man's friend
Adam-ın arkadaş-ı-ndan kitabı aldım - [Lit: Man-of friend-his-from book-the took-I]

Possessive Relationship Model

A note on separation of possessor and possessed

The Possessive Relationship may be separated by other words such as an adjective or an adjectival phrase:
Adamın eski arkadaşından - From the man's old friend
Adamın büyük ve pahalı arabasında - In the man's large and expensive car

Chaining Possessors
The chaining of Possessors is quite easy in Turkish, as follows:
evin kapısının penceresi - the house's door's window
And with various plural forms:
evin kapısının pencereleri - the house's door's windows
evlerin kapısının penceresi - the houses' door's window
- As you can see each "chained" Possessor takes both the Possessed Suffix in -i and the Possessor Suffix in -in [hence - kapı-sı -nın - door-the-of] , while the item Possessed takes the Possessed Suffix in -i - [hence pencere-si - window-the (Sing.) or pencere-ler-i - windows-the (Plural]
Further examples of chaining:
Ali'nin defterinin sayfları yırtılmıştır - Ali's notebook's pages are torn - [Lit: have been torn]
Bahçenin duvarlarının tuğlaları kırılmıştır. - The garden's walls' bricks are broken - [Lit: have been broken]
Mehmet'in bisikletinin lastikleri aşınılmıştır - Mehmet's bicycle's tyres are worn down - [Lit: have been worn down]
Arabamımızın motorunun benzin deposunun doldurma kapağı eksiktir - Our car's engine's petrol tank's filler cap is missing - [Lit: is absent, -tir makes this definite]
Note that the -tir suffix makes these sentences have a definite meaning.

In English we would say something like:
Ali's notebook pages are torn.
The garden walls' bricks are broken.
Mehmet's bicycle tyres are worn down.
But in Turkish these first nouns have to be made definite.

Possessive Constructions
The basis of a Possessive Construction is a noun such as iç - inside, interior.
With this we can form a Possessive Construction like - evin içi - the inside of the house.

Extended Forms
If the motion toward, static or motion away suffix is the added we have:
evin içine - into the house [to the inside of the house]
evin içinde - in the house [at the inside of the house]
evin içinden - from within the house [from the inside of the house]

Consider the following examples
Odanın içinde yer bulup oturdu. - He found a place in the room and sat down.
Bu kutuda ne var? - What is in this box?
Bilmem, içine bakmadım. - I don't know,I have not looked inside.
Bankanın içinden bir ses geliyordu. - A sound was coming from inside the bank.
Bu odanın içindekiler birbirine sohbet ediyor. - The people in this room are chatting to each other.

Omission of the Possessive Suffix
In many cases the suffix of Possession may be omitted from the first noun with very little difference in meaning:
Fabrikanın içinde çok insan çalışıyor. - Fabrika içinde çok insan çalışıyor.
- Both the above mean - Many people are working in the factory.
But in other cases there is a distinction in definiteness and specific meaning when the Possession Suffix is omitted from the first noun.

Definite Possession

Frequently the distinction is one of definiteness (or specificity). If the first noun carries the Possessive Suffix, it is definite (specific) and refers to a particular specific object known to the speaker.
Bu hayvanlar mağaranın içinde yaşar - These animals live inside the cave. [a definite cave]
Eşyalarımı kutunun içine koydum - I put my things into the box [A definite box]

Indefinite Possession

If however the Possessive Suffix is absent then the noun becomes indefinite and is often used in a general sense:
Bu hayvanlar mağara içinde yaşar - These animals live inside caves. [caves generally]
Eşyalarımı kutu içine koydum. - I put my things into a box/boxes [Indefinite box/boxes]

Idiomatic Forms of Possession

Sometimes the Possessive Compound corresponds to an idiomatic expression:
Ali'nin dairesi, şehrin içinde - Ali's office is (right) in the town
Ali'nin dairesi, şehir içinde - Ali's office is in town ("downtown" - USA usage)

Metaphorical Sense

Also the Possessive (genitive) is normally omitted when it is used in a metaphorical instead of actual physical sense:
Bir hafta içinde kitabını bitirecek. - He will finish his book within a week.
İki gün içinde geri döneceğim. - I'll return inside two days.

Demonstratives are Definite

However, when the first noun is already definite (as in the case of the Demonstrative Pronouns - this and that) then it must have a Possessor Suffix:
Bu şehrin içinde çok insan var. - There are many people (living) in this city.
Bu bahçenin içinde çok çeşit çiçek bulunur. - Many type of flowers are to be found in this garden.
Yangın, o adamın ofisin içinde başlamış. - Apparently [-mış] the fire started in that man's office.
O hayvanlar su mağaranın içinde yaşar - Those animals live inside that cave.