Need help to clarify the terms "arrival", "departure", "approach", "terminal" and "transition" fix for US STAR and SIDS
I am not an FAA controller or instrument rated but since you don't have an answer yet I will give it a shot.  If someone has a better answer please post:

Arrival:  IFR routes that start at radius about 30-50 NM from the airport.  This is where airplanes usually start their descent.  This can be controlled by en route or TRACON ATC.

Approach:  An IFR route that outlines a particular approach to the runway.  There are RNAV (GPS), VOR, and ILS approaches that are provided for an airport's runways.  You would file an approach during your IFR flight plan but could be modified by ATC as needed.  This is handled via ATC by approach control.  

Terminal:  The area handled by a TRACON (for busy airports).

Departure:  Your IFR route filed when you depart from the runway.  This is handled via ATC by Departure.

Transition:  I am not so sure on this but I think this relates to going from arrival to approach.