Yemen's main port (4)
I believe the answer is:
aden
'yemen's main port' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for aden that I've seen before include "Strange Dane to be in the Yemen" , "Yemeni gulf" , "Dean out in the seaport city" , "somewhere on the Arabian peninsula" , "Dane in seaport of Yemen" .)