Aid to meditation used by shaman, traditionally (6)
I believe the answer is:
mantra
'aid to meditation' is the definition.
(I've seen this before)
'used by shaman traditionally' is the wordplay.
'used by' says the answer is hidden in the clue.
'MANTRA' can be found hidden inside 'shaman traditionally'.
(Other definitions for mantra that I've seen before include "Powerful words" , "Repeated sacred word or words" , "Something said to focus concentration" , "Word or sound chanted repeatedly" , "Incantation, Hindu psalm" .)