Built-up area (4)
I believe the answer is:
town
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">built-up area</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 town that I've seen before include "Small urban development" , "Person employed to make public announcements" , "Built up area" , "Milton Keynes, say, with 1a [NEW]" , "Large urban area" .)