What Does Number Lock Mean?
Number lock (num lock) is a key on a typical computer keyboard. It is a type of toggle key that, when switched on, enables the user to use the numeric keys on the keyboard, and when switched off, enables the use of other functionalities associated with the keys. The status of the key is usually indicated with the help of an LED in the button or on the top corners of the keypad. Num locks are implemented in various ways in different keyboard layouts, and are beginning to fall out of use on some smaller keyboard layouts.
Techopedia Explains Number Lock
Number lock is a toggle key similar to the caps lock and scroll lock keys. It was introduced as a way to add extra functionality to the numeric keys, as early keyboards had fewer keys. When the num lock is on, the keys are used to input numeric characters and when it is off, the keys take on other roles, frequently as directional keys. For instance, pressing the number 8 key when num lock is enabled inputs the value 8, whereas the same action would represent a cursor moved upward if num lock is disabled. In some computers, the key is also used to convert the main keyboard to a numeric keypad.
The number lock usually has its own dedicated key. However, in some computers the num lock is activated by a combination of key presses that may include a function key and some other key combination. Num lock can also be enabled or disabled on startup by making some changes to the keyboard settings. In Apple computers, the num lock is known as the clear key, and it has a slightly different purpose. Clear keys are used in full-size keyboards that have separate numeric keys and are commonly used for numeric inputs and not for cursor control.
As keyboard sizes have grown and became able to accommodate separate numeric keypads and arrow keys, the need for the num lock has decreased, but they are still included in most modern keyboards for convenience and simply because people are used to having that function. However, on certain keyboards, especially laptop keyboards, the num lock key has been replaced with a combination key.