Crux of the matter (4)
I believe the answer is:
gist
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">crux of the matter</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for gist that I've seen before include "Essence; meaning" , "General meaning or main point" , "Main points" , "Core meaning" , "Central idea" .)