Liquid measures (6)
I believe the answer is:
litres
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">liquid measures</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for litres that I've seen before include "Let Sir get the liquid amounts" , "Liquid measures" , "Amounts of water" , "Metric units of capacity" , "Cubic capacities" .)