Name for religious leader, holy American (4)

I believe the answer is:

pius

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'name for religious leader' is the definition.
I can't judge whether this definition defines the answer.

'holy american' is the wordplay.
'holy' becomes 'pi' (I've seen this in other clues).
'american' becomes 'us' (abbreviation for United States).
'pi'+'us'='PIUS'

Can you help me to learn more?

(Other definitions for pius that I've seen before include "WW two Pope (XII)" , "Name of twelve Popes" , "old pope" , "religious leader" .)

I've seen this clue in The Times.

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