Iran aids revolution in Mediterranean island (8)
I believe the answer is:
sardinia
'mediterranean island' is the definition.
(I've seen this before)
'iran aids revolution' is the wordplay.
'revolution' is an anagram indicator.
'iran'+'aids'='iranaids'
'iranaids' with letters rearranged gives 'SARDINIA'.
'in' is the link.
(Other definitions for sardinia that I've seen before include "Adrian is seen in Mediterranean island" , "Corsican neighbour" , "Island south of Corsica" , "Island belonging to Italy" , "Second-largest Mediterranean island, after Sicily" .)