A bedroom is a room in a house for the bed, so it’s mainly used for sleeping. If you live in a one-bedroom apartment, it has exactly one room for the bed. To sound old fashioned, call it your bedchamber.
If your home has three bedrooms, you can describe it as a "three-bedroom house." While you might do homework, watch TV, or even entertain friends in your bedroom, it probably has a bed in it, and the main purpose of the room is sleeping. You can also use the term "bedroom community" to mean a suburb — a town that's close enough to a city that people can commute there for work and come back to their own bedrooms at night.