Mountain ridge (5)
I believe the answer is:
arete
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mountain ridge</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 arete that I've seen before include "part of mountain range" , "feature of range" , "Sharp ridge on mountain, with a tree" , "Narrow mountain ridge - eater (anag)" , "Glacial ridge" .)