Container weight (4)
I believe the answer is:
tare
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">container weight</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 tare that I've seen before include "Vehicle's empty weight" , "Variety of vetch" , "Biblical weed" , "Vetch plant" , "Weight of container makes a vetch" .)