Path of a planet (5)
I believe the answer is:
orbit
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">path of a planet</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 orbit that I've seen before include "Path through space" , "Range of influence" , "Rotating path" , "field of activity" , "Track of satellite" .)