Instrument for Orpheus (4)
I believe the answer is:
lyre
'instrument for orpheus' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for lyre that I've seen before include "Instrument played by Orpheus" , "Early harp" , "Music-maker" , "Ancient Greek stringed instrument" , "Rely (anag.)" .)