Small barrel (3)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">small barrel</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for keg that I've seen before include "Small cask or barrel" , "What's found at King's Head" , "Small beer cask" , "Sort of beer" , "Barrel as for beer" .)
(Other definitions for firkin that I've seen before include "Brewing measure equal to 9 gallons" , "Nine-gallon wooden keg" , "Small cask formerly used for liquids" , "Wooden keg with 9 imperial gallons" , "Brewing measure of nine gallons" .)