A doorknob is a mechanical device used to open and close doors. Typically made of materials like metal or plastic, doorknobs are designed to be grasped and turned. They often come in various shapes and styles, allowing for both functional and aesthetic purposes in homes and buildings. Doorknobs usually operate a latch mechanism that secures the door when closed. Some doorknobs also include a locking feature for added security. They can be found on interior and exterior doors, and their design can vary widely, from simple round knobs to more elaborate designs that enhance the overall decor of a space.