Sky (9)
I believe the answer is:
firmament
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sky</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 firmament that I've seen before include "Sky (literary)" , "The celestial sphere" , "Heavens, sky" , "The starry heaven" , "outer space, encapsulated" .)