A door knob is a round or oval handle used to open and close doors. Typically made of materials like metal, plastic, or glass, door knobs are designed to be grasped and turned. They often feature a mechanism that latches the door when closed, providing security and privacy. Door knobs come in various styles and finishes, allowing them to match different types of decor. Some knobs are simple and functional, while others are decorative, enhancing the overall appearance of a room. They can be found on residential doors, commercial buildings, and even cabinets, making them a common household item.