Gorge or ravine (6)
I believe the answer is:
canyon
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">gorge</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that gorge can be written as canyon)</span><br/ ><br/ >'<span class="explanation-format__original">ravine</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that canyon is a type of ravine)</span><br/ ><br/ ></span>
(Other definitions for canyon that I've seen before include "Deep, steep-sided valley" , "The Grand . . . . . . of Colorado is a natural phenomenon in USA" , "Deep fissure" , "'Deep ravine, gorge (6)'" , "Gulf" .)