A function key is a key on a computer or terminal keyboard which can be programmed so as to cause an operating system command interpreter or application program to perform certain actions, a form of soft key. On some keyboards/computers, function keys may have default actions, accessible on power-on.
Surge definition, a strong, wavelike, forward movement, rush, or sweep: the onward surge of an angry mob. See more.
Something which is transient. (physics) A transient phenomenon, especially an electric current; a very brief surge. (acoustics) A relatively loud, non-repeating signal in an audio waveform which occurs very quickly, such as the attack of a snare drum.