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.
A compressor surge is a disruption of the airflow through the aircraft engine, if it happened to your car, it goes stuttering and gives poor response. Keep an eye on our blog, there are nice themes where you may be interested in.