What are mode keys?

Mode keys are special keys on a keyboard that switch the function of other keys or modify their behavior, allowing users to access additional features or commands without needing extra keys. Common examples include the Shift, Alt, and Ctrl keys, which enable different inputs when pressed in combination with other keys. In some software or hardware contexts, mode keys can also refer to keys that toggle between different operating modes, altering how the device or application responds to user input.