Star element (4)
I believe the answer is:
lead
I believe this is a double definition.
'star' is the first definition.
(I've seen this before)
'element' is the second definition.
(lead is a kind of element)
(Other definitions for lead that I've seen before include "Travel in front of" , "Metal - van - go ahead" , "Principal performer" , "in first place" , "Be in charge of, element" .)