Viz (6)
I believe the answer is:
namely
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">viz</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for namely that I've seen before include "Viz" , "Old especially" , "Videlicet" , "That is to say, specifically" , "to wit" .)