The eighth planet from the sun (7)
I believe the answer is:
neptune
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">the eighth planet from the sun</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 neptune that I've seen before include "Poseidon" , "King of the sea" , "Remote planet" , "Third largest of the planets, and sea god" , "One distanced from The Sun" .)