Depends what kind of room you want to talk about.

A room in a normal house or apartment is 部屋. This extends to names of the rooms, which don't have a standard name, e.g. おもちゃ[部屋]{べや} "play room". You can also say 遊ぶ部屋.

Special-purpose rooms usually end in [室]{しつ}, e.g. 事務室, 図書室, 洗濯室.

If your rooms are numbered, they are usually numbered as 132号室.

Note that 部屋 is a bit broader than the English "room". 132号室 could be a small apartment, consisting of several rooms.