Two pints (5)
I believe the answer is:
quart
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">two pints</span>' is the definition.<br/ ><span class="explanation-format__explanation">(unit of liquid equal to two pints)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for quart that I've seen before include "water may be measured in this" , "Liquid measure" , "A couple of pints" , "Two imperial pints" , "The capacity" .)