Port found in a study (4)
I believe the answer is:
aden
'port' is the definition.
(I've seen this before)
'a study' is the wordplay.
'study' becomes 'den' (I've seen this before).
'a'+'den'='ADEN'
'found in' is the link.
(Other definitions for aden that I've seen before include "Commercial capital of Yemen" , "Port city of Yemen" , "Main port of Yemen" , "Strange Dane to be in the Yemen" , "Former Br. Gulf colony" .)