A sound way to make expiation (5)

I believe the answer is:

atone

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'way to make expiation' is the definition.
I can't judge whether this defines the answer.

'a sound' is the wordplay.
'sound' becomes 'tone' (tone is a kind of sound).
'a'+'tone'='ATONE'

Can you help me to learn more?

(Other definitions for atone that I've seen before include "Make up, compensate (for)" , "Make amends (for something)" , "Make redress" , "Expiate" , "Pay the price" .)

I've seen this clue in the Evening Standard.

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