Narrow lowland (4)
I believe the answer is:
glen
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">narrow lowland</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for glen that I've seen before include "Narrow, deep mountain valley" , "Narrow Scots valley" , "Long narrow valley in Scotland" , "Depression in Scotland" , "Scottish or Irish valley" .)