Roman army division (6)
I believe the answer is:
legion
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">roman army division</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 legion that I've seen before include "Vast multitude" , "Large body of soldiers" , "A great number in the Roman military unit" , "Division of ancient Roman army" , "Roman battalion" .)