In a building or large vehicle, like a ship, a room is any enclosed space within a number of walls to which entry is possible only via a door or other dividing structure that connects it to either a passageway, another room, or the outdoors, that is large enough for several people to move about, and whose size, fixtures, furnishings, and sometimes placement within the building or ship support the activity to be conducted in it.
Historically, the use of rooms dates at least to early Minoan cultures about 2200 BC, where excavations at Akrotiri on Santorini reveal clearly defined rooms within certain structures.
In early structures, the different room types could be identified to include bedrooms, kitchens, bathing rooms, closets, reception rooms, and other specialized uses. The aforementioned Akrotiri excavations reveal rooms sometimes built above other rooms connected by staircases, bathrooms with alabaster appliances such as washbasins, bathing tubs, and toilets, all connected to an elaborate twin plumbing systems of ceramic pipes for cold and hot water separately. Ancient Rome manifested very complex building forms with a variety of room types, including some of the earliest examples of rooms for indoor bathing. The Anasazi civilization also had an early complex development of room structures, probably the oldest in North America, while the Maya of Central America had very advanced room configurations as early as several hundred AD. By at least the early Han Dynasty in China (e.g. approximately 200 BC), comfort room complex multi-level building forms emerged, particularly for religious and public purposes; these designs featured many roomed structures and included vertical connections of rooms.
Some rooms were specially designed to support the work of the household, such as kitchens, pantries, and root cellars, all of which were intended for the preparation and storage of food. A home office or study may be used for household paperwork or external business purposes.