door

A door is a movable barrier that controls access between spaces, provides privacy, security, and protection from weather. The word originates from Old English dur, related to Proto-Germanic roots.

Doors vary by mechanism and appearance. Hinged doors are the most common, swinging on vertical hinges. Sliding doors move along a track; pocket doors slide into a wall cavity. Other types include revolving doors, French doors with multiple panels, and barn or Dutch doors that separate while allowing visibility.

Materials include wood, metal, glass, and composites. Doors can be solid core, hollow core, or fire-rated. Hardware includes hinges, handles or knobs, locks, strike plates, and closers. Weather stripping and thresholds seal against drafts and moisture.

Design considerations include size, fire rating, acoustic insulation, safety, and accessibility. Standard interior doors are typically 30–36 inches wide; exterior doors often larger. Lever handles are preferred for accessibility; automatic or semi-automatic doors are used in high-traffic or public buildings.

Historically, doors appear in ancient architecture to mark thresholds and provide defense. Techniques evolved from heavy wooden panels to modern molded cores and smart-locking systems.