Big container (3)
I believe the answer is:
vat
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">big container</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 vat that I've seen before include "A tax on a large container?" , "Barrel - tax" , "Large container for liquid" , "Large tub; tax" , "Large tank or vessel" .)