Stages turn or star turns (6)
I believe the answer is:
rostra
'stages' is the definition.
(I've seen this before)
'turn or star turns' is the wordplay.
'turn' says the letters should be written in reverse.
'turns' indicates anagramming the letters.
'or' written backwards gives 'ro'.
'star' with letters rearranged gives 'stra'.
'ro'+'stra'='ROSTRA'
(Other definitions for rostra that I've seen before include "where they make their speeches?" , "Raised platforms" , "stages" , "The beaks" .)