Connecting strip of land (7)
I believe the answer is:
isthmus
'connecting strip of land' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for isthmus that I've seen before include "Neck of land connecting larger areas" , "Constriction" , "Narrow strip linking two larger areas of land" , "Narrow land bridge" , "Narrow strip of land connecting two larger areas" .)