Unit of weight, for short (4)
I believe the answer is:
kilo
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">unit of weight for short</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 kilo that I've seen before include "Metric weight, informally" , "Unit of weight (abbr)" , "Unit of mass" , "2.2 lbs" , "Lewis Carroll heroine" .)