salonu

In a sentence

• Idę do salonu, żeby odpocząć.

  I'm going to the living room to relax.

  Here, 'salonu' is used to refer to the living room in a house (genitive case, indicating direction towards).

• Kolor ścian salonu jest bardzo elegancki.

  The color of the living room's walls is very elegant.

  In this sentence, 'salonu' is in the genitive case, indicating possession ('of the living room').

• Czytałem wczoraj książkę w salonu.

  I was reading a book in the living room yesterday.

  This is actually incorrect usage— the correct form for location in a place would be 'w salonie' (locative case), but this demonstrates a common learner mistake focusing on the word form.