Celestial belt (6)
I believe the answer is:
zodiac
'celestial belt' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for zodiac that I've seen before include "Heavenly belt of star-signs" , "Astrologers' twelve signs" , "Diagram of astrological signs" , "Heavenly region" , "It's divided into 12 signs" .)