Definition: function key
A set of keyboard keys that are used to command the computer. Typically 12 keys labeled F1, F2, etc., their purpose is dependent on which operating system and application are running at the time they are pressed. Each key can be made to perform up to seven separate operations: the key pressed alone or with one or more of the Shift, Control and Alt keys held down at the same time. On the Mac, the Command and Option keys are the Control and Alt key counterparts.
Across the Top
Special Function Keys
A Different Function Key
Function keys (F keys) are typically located in a horizontal row across the top above the numeric keys. They may also be only on the left side or repeated on the left side of the keyboard.
Many keyboards have additional keys for launching applications, playing media and opening folders (see special function key).
Although "Fn" stands for "function," the Fn key is entirely different from F1, F2, etc. Holding down Fn activates a dual-purpose key (see Fn key).