Canon hiding billion in cash for Russian (5)
I believe the answer is:
ruble
'cash for russian' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'canon hiding billion' is the wordplay.
'canon' becomes 'rule' (canon can mean a rule or principle).
'hiding' is an insertion indicator.
'billion' becomes 'b'.
'rule' enclosing 'b' is 'RUBLE'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for ruble that I've seen before include "Unit of money in Russia" , "ready in Russia" , "Russian currency" .)