Chest and back armour (7)
I believe the answer is:
cuirass
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">chest and back armour</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for cuirass that I've seen before include "Large piece of armour enveloping the upper body" , "Upper-body armour piece" , "Some mail" , "Item of armour" , "Chest and back armour" .)