Option key
Keyboard key found on Apple computers that is used as a modifier for other command codes. As can be seen by the picture to the right, the option key is found to the right of the command key and since the mid 1990s also includes the small "alt" text also on the key.
Users more familiar with the PC can think of this key as the Alt key on their keyboards.
Also see: Alt key, Apple definitions, Command key, Keyboard definitions, Modifier key