Togetherness (6)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">togetherness</span>' is the definition.<br/ ><span class="explanation-format__explanation">(being united or together)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for unison that I've seen before include "Total agreement or concord" , "with regard to the pitch" , "All singing the same notes" , "Harmony - public services' trade union" , "All singing the same note" .)