A doorknob is the round handle you turn to open a door. When you grip it and twist, the mechanism inside pulls back a metal latch that holds the door closed, allowing the door to swing open. Many doorknobs work in a similar way, though the direction you turn them can vary.

Doorknobs are such a common part of daily life that we barely notice them until one breaks or gets stuck. They come in different materials (brass, steel, glass, ceramic) and styles, from simple round knobs to fancier designs with decorative details. Some old houses have crystal doorknobs that catch and reflect light beautifully.

The word can also describe someone who isn't very bright or aware, though this usage is unkind. If someone calls another person a doorknob, they're comparing that person to an inanimate object, which is a pretty rude thing to say.

Before doorknobs became common in the 1800s, people used latches, bars, or simple handles to open doors. The modern doorknob made doors more secure and easier to use, though today many buildings use lever handles instead because they're easier to operate when your hands are full.