Great divide (4)
I believe the answer is:
gulf
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">great divide</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 gulf that I've seen before include "Deep inlet of sea; chasm" , "Deep inlet of the sea almost surrounded by land" , "Deep wide chasm" , "Rift" , "Large inlet of the sea" .)