A bonus room is a large room in a house which can be used as a multi-purpose area. A bonus room, unlike an American bedroom, does not usually contain a closet. A bonus room might be used as a family room, sewing or hobby room, game room, home cinema, office, or den. It is sometimes over a garage or in an attic area with partially reduced ceiling height or some other less desirable characteristic. It may be a room that cannot legally be described as a bedroom (because of inadequate ceiling height, poor fire safety features, etc.).
The term bonus room is mainly used in the United States. One early use is from The New York Times in 1991, which described it as "A recent solution to the problem of noisy teen-agers is the enticingly titled bonus room, which is a spare room on the bedroom floor that can be used as a den, television room or guest room."