What's hotkey?

what is HOT KEY, and wats it for..

A keyboard shortcut (or accelerator key, shortcut key, hot key, key binding, keybinding, key combo, etc.) is a key or set of keys that performs a predefined function. These functions can often be done via some other, more indirect mechanism, such as using a menu, typing a longer command, and/or using a pointing device. By reducing such sequences to a few keystrokes, this can often save the user time, hence shortcut.

Source: http://en.wikipedia.org/wiki/Hot_key

The key or key combination that causes some function to occur in the computer, no matter what else is currently running. It is commonly used to activate a memory resident (TSR) program.