Door

A door is a movable structural element used to open or close an entrance to a room, house, building, or vehicle. It typically consists of a panel (the door leaf) and a frame structure around it called a doorframe or door jamb, which is fixed to the wall. Small hinges called hinges allow the panel to swing on the frame.

A door serves two related functions: controlled access and security. When closed, it prevents unwanted people, air, sound, and fire from entering; when open, it permits passage. Door design therefore depends on its intended use: domestic doors, fire doors, and security doors each have different requirements.

Components of a door

The leaf is the main moving part. The doorframe is the fixed structure attached to the wall. Hinges connect the two. The handle and lock are used to open, close, or hold the door in position. Some doors are fitted with windows, vents, or peepholes for various purposes.

Types of opening

A standard hinged door swings on hinges to one side. A sliding door moves along a track or rail and is used in confined spaces. A folding door divides into several panels. A revolving door rotates on a central pivot, controlling air flow and heat loss in large buildings.

Materials

Wood has historically been the most common material. In recent times, steel, aluminium, composite wood-metal, and PVC plastic have been used. Material choice affects door weight, heat transmission, and fire resistance. Fire-rated doors are assessed by the length of time they can withstand fire.

Cultural significance

In many parts of the world, doors carry social meaning beyond function: they mark the boundary between public and private space. They appear in proverbs, wedding customs, and cultural traditions regarding thresholds. In historic cities, decorated doors reflect regional craftsmanship.