Skirting (4)
I believe the answer is:
dado
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">skirting</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 dado that I've seen before include "Differently finished lower part of an interior wall" , "Border along an inside wall" , "Wood border running round room walls" , "Architectural feature" , "Differently decorated lower part of an inside wall" .)