Company number?
I believe the answer is:
two
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">company number?</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 two that I've seen before include "Number in pair" , "prime -- that's not odd" , "One plus one" , "not very many" , "Company, so it's said" .)