Piece of music child put on a tad short (6)
I believe the answer is:
sonata
'piece of music' is the definition.
(type of musical composition)
'child put on a tad short' is the wordplay.
'child' becomes 'son' (male child).
'put on' is a charade indicator (letters next to each other).
'short' means to remove the last letter.
'tad' with its final letter removed is 'ta'.
'son'+'a'+'ta'='SONATA'
(Other definitions for sonata that I've seen before include "See 6" , "eg Moonlight, Kreutzer" , "Work for soloist" , "To NASA, strangely, for the solo piece" , "Type of musical composition" .)