Aid must be redirected to the arena (7)
I believe the answer is:
stadium
'the arena' is the definition.
(synonyms)
'aid must be redirected' is the wordplay.
'be redirected' indicates anagramming the letters.
'aid'+'must'='aidmust'
'aidmust' anagrammed gives 'STADIUM'.
'to' is the link.
(Other definitions for stadium that I've seen before include "bowl?" , "A major sports ground" , "Venue for sporting events, concerts etc" , "Sports ground as for athletics" , "Large structure for open-air sports" .)