Key
A key may refer to any of the following:

1. With a computer keyboard, a key is one of the keyboard's buttons. Letters, numbers, functions, and symbols are all represented on keys. For example, the picture shows the Windows key, a keyboard key found on most keyboards today.
When a keyboard key is pressed down, that key is sent as input to the computer and appears on the screen. For example, clicking in the following box with your mouse and typing any letter key on the keyboard makes it appear.
2. A key is a tool to lock and unlock a computer, computer drive, or another computer-related device. If you have lost the key to your computer device, Computer Hope cannot help you recover it. Contact the manufacturer of the product that is locked.
3. With the Microsoft Windows registry, a registry key is a single registry item whose value(s) can be modified.
4. The term key or keyed describes a cable with physical dimensions causing a cable, such as a ribbon cable, to connect only one direction. In rare cases, this may prevent a cable from connecting correctly to a drive. For example, a floppy disk drive manufacturer may have keyed their connection differently than the cable manufacturer. In this situation, the user may be required to purchase a different cable or floppy drive or modify the key on the cable.
5. With encryption, a key is a set of instructions to encrypt and decrypt data.
6. When describing a unique number or identification, a key describes a product key.
Any key, FN key, Function keys, Hard drive terms, Hardware key, Keyboard terms, Keystroke, Special key