Little-pigs complement (5)
I believe the answer is:
three
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">little-pigs complement</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 three that I've seen before include "So many 12s today" , "Sixth root of seven hundred and twenty nine" , "Number of strikes before you're out" , "Number of blind mice" , "trilogy" .)