Shelf support (7)
I believe the answer is:
bracket
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">shelf support</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 bracket that I've seen before include "L-shaped support - one of a pair enclosing text" , "L-shaped shelf support" , "Supporter" , "Parenthesis" , "Classification" .)