Betelgeuse's constellation (5)
I believe the answer is:
'betelgeuse's constellation' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for orion that I've seen before include "Mythical great hunter" , "Mythical Greek hunter turned into constellation" , "Greek hunter became a constellation" , "Great hunter of Greek myth, and a constellation" , "Constellation in the form of a belt" .)