The term "lavatory" has several meanings, all of which relate to washing, hygiene, and cleanliness. A lavatory may be a sink or washbasin meant for cleaning the hands and face. It may also be a receptacle for the elimination of bodily wastes. In many societies, the term is applied more generally, and may refer to a room or small building in which these functions of washing and elimination take place. Lavatories have many other names, and the precise design and organization of lavatories varies widely from culture to culture.
Originally, lavatories were simply facilities for washing. The Latin root of this term was, and is, used among members of Christian monastic orders, who made use of such washing-room facilities for both practical and ritual cleansing. The monastic significance of this term remains, but it has been eclipsed by the common practice of using the term to refer to a water closet or toilet area more generally. In some cases, particularly in the British Isles, the term may be used to specifically refer only to the toilet itself.
A typical western example contains a toilet for the elimination of waste, and a basin or bowl with a water supply and drain for use in personal washing. A lavatory in a private home in the west will often include bathing facilities as well, and in American usage the term "bathroom" is roughly synonymous with "lavatory". Some western cultures place a bidet in the room as well, but this is not universally done.
Some societies separate the cleaning and waste elimination functions of a lavatory. This is especially common in larger communal lavatories. Certain cultures, especially those in Eastern Europe, also display a preference for this configuration in private facilities as well.
The specific form of equipment within a lavatory varies widely from culture to culture. The western world, and areas colonized or influenced by the west, usually makes use of a seated flush toilet that uses water and a vacuum created by water pressure to eliminate waste. In other parts of the world, a lavatory is much more likely to contain a receptacle designed to facilitate the elimination of waste while squatting rather than sitting.
Specialized sorts of lavatories have been designed for use in unusual circumstances. Portable lavatories may use chemical agents to neutralize waste instead of water to flush it away. The lavatory facilities in aircraft and trains are much more compact than those for normal home use. Astronauts make use of special equipment in their lavatories to account for the difficulties posed by working in a zero-gravity environment.