The place where something begins (6)
I believe the answer is:
source
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">the place where something begins</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for source that I've seen before include "Well" , "Fountainhead - journalist's informant" , "Where something originates" , "Find" , "Origin or starting point" .)