Narrow strip of land (7)
I believe the answer is:
isthmus
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">narrow strip of land</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for isthmus that I've seen before include "Narrow land bridge" , "Narrow strip of land in sea" , "Neck of land connecting larger areas" , "Narrow strip of land with water on two sides" , "Narrow strip of land between two larger ones" .)