Permanent army post (4)
I believe the answer is:
fort
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">permanent army post</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for fort that I've seen before include "& 22 US Army post" , "Garrison" , "Defensive building" , "Military building" , "& 4 Down Army post in USA" .)