A doorknob is a rounded handle used to open and close doors. It is typically mounted on a door and can be turned to disengage a latch, allowing the door to swing open. Doorknobs come in various materials, including metal, plastic, and glass, and can have different designs to match the style of a home or building. Doorknobs are often part of a larger hardware set that includes door hinges and locks. They can be operated with one hand, making them convenient for everyday use. Some doorknobs also feature a locking mechanism for added security.