A dozen (6)
I believe the answer is:
twelve
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">a dozen</span>' is the definition.<br/ ><span class="explanation-format__explanation">('twelve' can be a synonym of 'dozen')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for twelve that I've seen before include "Lunchtime" , "Number of centuries needed for MCC" , "Apostles and members of the jury" , "Midnight or noon" , "One under a baker's dozen" .)