Crossword Genius

In jazz, briefly, I form a trio (5)


I believe the answer is:


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Here is my best explanation:

'a trio' is the definition.
('triad' can be a synonym of 'trio')

'in jazz briefly i form' is the wordplay.
'in' is an insertion indicator.
'jazz' becomes 'trad' (trad jazz is a type of jazz).
'briefly' means to remove the last letter.
'form' becomes 'd' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'trad' with its final letter taken off is 'tra'.
'tra' going around 'i' is 'tria'.

Can you help me to learn more?