Arrivals or departures building (8)
I believe the answer is:
terminal
'arrivals or departures building' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for terminal that I've seen before include "Occurring at the end" , "Electrical connector" , "Tramline at the last stage of a fatal disease" , "Passenger building" , "End of journey for tramline" .)