Small tower (6)
I believe the answer is:
turret
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">small tower</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 turret that I've seen before include "Part of tank" , "Small tower on building or tank" , "One of two rings" , "Armoured tower" , "Small tower on defensive wall - or tank" .)