A cellar is one or more rooms of a building that are below ground level. In American English, the term cellar is mostly used for small, single underground rooms, such as those used for storage of wine etc., whereas a complete underground floor of a building (or several such floors) are called basement. In British English, the term cellar is used for both things, and the term basement is only used when referring to public buildings such as department stores, but rarely when referring to private houses.
Cellars/basements may have small windows high up the wall, or no windows at all. Traditionally, cellars/basements were used mainly as storage rooms and tended to be dark (especially before the advent of electric light), often cold, humid, unfinished, dirty and not very cosy. Because of this, weak-spirited adults and children were often afraid to go on the cellar/basement. Sometimes misbehaved or disobedient children were locked in a cellar for punishment. An old-style cellar may also be found a suitable setting for BDSM play and corporal punishment due to its frightening, prison and dungeon like style and the fact that it is often windowless, secluded and relatively soundproof.