Revolutionary band in Lebanese port (4)
I believe the answer is:
tyre
I believe this is a double definition.
'revolutionary band' is the first definition.
(band of rubber around a wheel, which revolves)
'lebanese port' is the second definition.
(port city in Lebanon)
'in' is the link.
(Other definitions for tyre that I've seen before include "Part of car; old Lebanon port" , "Pneumatic device on wheel" , "Rubber wheel-ring" , "Biblical town" , "Old Phoenician port" .)