Supremes singer Diana (4)
I believe the answer is:
ross
'supremes singer diana' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ross that I've seen before include "Diana --, Motown singer" , "- and Cromarty, former Scottish county" , "Macbeth thane; a T. E. Lawrence pseudonym" , "Wye town; Antarctic sea" , "-- And Cromarty, former county of Scotland" .)