Mark the boundaries of (7)
I believe the answer is:
delimit
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mark the boundaries of</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for delimit that I've seen before include "Mark boundary" , "Set boundaries" , "Mark boundaries of" .)