odaja

1. formal (in a palace, castle, tomb) chamber; room
   U dvorcu ima više od sto odaja. — The castle has more than a hundred rooms.
   Kraljica se povukla u svoje odaje. — The queen withdrew to her chambers.
   Arheolozi su otkrili tajnu odaju u piramidi. — Archaeologists discovered a secret chamber in the pyramid.

Mostly used for rooms in palaces, castles and old buildings; for an ordinary flat, soba is used.