Gangway (5)
I believe the answer is:
aisle
'gangway' is the definition.
(synonyms)
This is all the clue.
(Other definitions for aisle that I've seen before include "Walkway between seats" , "Passageway in church as for bride" , "Passages between seating areas" , "way for prospective union members?" , "Passageway in theatre" .)