In most cases the interior side of a door matches its exterior side but, in some other cases, there are sharp contrasts between the two sides, such as in the case of a vehicle door.
The earliest in records are those represented in the paintings of the Egyptian tombs, in which they are shown as single or double doors, each in a single piece of wood.
For example, being granted access to a door, including the guarding or receiving of the key to that door, may have special significance.
Similarly, doors and doorways frequently appear in literature and the arts in metaphorical or allegorical context, often as a portent of change.
A door is a moving mechanism used to block off, and allow access to, an entrance to or within an enclosed space, such as a building, room or vehicle.
Doors normally consist of one or two solid panels, with or without windows, that swing on hinges horizontally.
The stiles were the vertical boards, one of which, tenoned or hinged, is known as the hanging stile, the other as the middle or meeting stile.
As a form of courtesy and civility, people often knock before opening a door and entering a room.
Doors are often symbolically endowed with ritualistic purposes.
When closed, a door normally impedes the transfer of air from one side to the other.
Similar structures that do allow air to be transferred through some form of a grillwork are called gates.