Highland valley (4)
I believe the answer is:
glen
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">highland valley</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 glen that I've seen before include "Narrow, deep mountain valley" , "Highland valley" , "Narrow valley with a stream" , "Scottish or Irish valley" , "Campbell perhaps" .)