Buddhist chant supports old Ugandan saying (5)
I believe the answer is:
idiom
'saying' is the definition.
(idiom is a kind of saying)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for idiom that I've seen before include "Artistic style" , "Special turn of phrase" , "Peculiar term" , "Group of words in which the meaning may not be obvious" , "Distinctive expression" .)