Atmospheric phenomenon (6)
I believe the answer is:
aurora
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">atmospheric phenomenon</span>' is the definition.<br/ ><span class="explanation-format__explanation">(aurora is a kind of atmospheric phenomenon)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for aurora that I've seen before include "Dawn goddess; polar lights" , "Roman Godess of the Dawn" , "7 ... borealis, ... lights" , "Display of lights in the night sky" , "Northern or southern lights" .)