Real Dictionary

room
countable noun: A room is one of the separate sections or parts of the inside of a building. Rooms have their own walls, ceilings, floors, and doors, and are usually used for particular activities. You can refer to all the people who are in a room as the room.
countable noun: If you talk about your room, you are referring to the room that you alone use, especially your bedroom at home or your office at work.

room in American English
space, esp. enough space, to contain something or in which to do something
intransitive verb: to occupy a room or rooms; lodge
noun: a portion of space within a building or other structure, separated by walls or partitions from other parts

room in British English
noun: space or extent, esp unoccupied or unobstructed space for a particular purpose