Arabian seaport (4)
I believe the answer is:
aden
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">arabian seaport</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for aden that I've seen before include "Yemeni port" , "Yemen's chief port" , "Main port of Yemen" , "Port city of Yemen" , "Commercial capital of Yemen" .)