Doors are movable barriers used to open and close entrances, rooms, or compartments within buildings. Constructed from wood, metal, fiberglass, or composite materials, they serve both functional and aesthetic purposes by providing privacy, security, and sound insulation. Interior doors often feature smooth finishes and simple designs to match room decor, while exterior doors are built for durability and weather resistance, with reinforced frames and locking mechanisms. Modern doors include energy-efficient models with insulated cores and weather stripping to reduce heat loss. They are available in various styles—sliding, swinging, or French—to suit architectural themes and space constraints. Safety standards require doors to meet fire-resistance and accessibility guidelines, especially in public buildings. Proper installation ensures smooth operation and long-term performance. Doors also contribute to home security when paired with deadbolts and smart locks. Thoughtfully chosen doors enhance both the appearance and functionality of a structure while promoting comfort and peace of mind for occupants.