Duplex apartment (10)
I believe the answer is:
maisonette
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">duplex apartment</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 maisonette that I've seen before include "possible place to live" , "Two-story flat" , "dwelling place" , "Small house, flat" , "small property" .)