Crossword Genius

Air of trio playing - more sound? (1,8)

Ross

I believe the answer is:

a fortiori

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'more sound?' is the definition.
Both the definition and answer are adverbs. Maybe you can see an association between them that I can't see?

'air of trio playing' is the wordplay.
'playing' indicates an anagram.
'air'+'of'+'trio'='airoftrio'
'airoftrio' with letters rearranged gives 'A FORTIORI'.

Can you help me to learn more?

(Other definitions for a fortiori that I've seen before include "stronger premises" , "even more convincing reasons" , "more convincing reason" , "with greater reason" , "Latin phrase: With even stronger reason than that already accepted" .)

I've seen this clue in The Independent.
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