Composer Copland
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
'composer copland' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for aaron that I've seen before include "Elder brother of Moses" , "OT character" , "Fanfare for the Common Man composer" , "- - Copland (mus.)" , "leader's brother" .)