In the construction “house's door": house is the owner, door is the owned.
Suffix: -(n)in (4) (stressed)
Conjugation letter: n (if the word doesn't end in a consonant)
The single exception:
Exception: Words of foreign origin ending in b/c/d are hardened to end in p/ç/t, because b/c/d normally cannot end a word in Turkish. However, when a suffix is added, these letters do not end the word any longer, so they are often softened back to the original form. Examples: