Large bodies of water (6)
I believe the answer is:
oceans
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">large bodies of water</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for oceans that I've seen before include "Arctic and Indian" , "Atlantic, Pacific etc" , "Large amounts (of water)" , "Large seas" , "Large bodies of water" .)