Script unit (4)
I believe the answer is:
line
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">script unit</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 line that I've seen before include "classified information" , "cover on the inside" , "Formation of one beside another" , "Dress" , "Some poetic feet; boundary, when drawn" .)