Open-air rooms (5)
I believe the answer is:
atria
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">open-air rooms</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 atria that I've seen before include "Lobbies" , "Open courts of Roman houses" , "Central courts (in ancient Rome or shopping arcades)" , "Covered courts" , "Public spaces with galleries" .)