Hawaiian island or porch (5)
I believe the answer is:
lanai
This clue is a double definition.
'hawaiian island' is the first definition.
(I've seen this in another clue)
'porch' is the second definition.
(I know that lanai is a type of art gallery)
(Other definitions for lanai that I've seen before include "Hawaiian veranda" , "Hawaiian living area" , "Place where Hawaiians live" .)