Open-sided gallery (6)
I believe the answer is:
loggia
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">open-sided gallery</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 loggia that I've seen before include "Structure similar to verandah" , "Open-sided gallery or arcade" , "Covered arcaded gallery" , "Open-sided gallery for viewing" , "Covered arcade, Italian-style" .)