noun
1
BAD : Nowadays I prefer classical musics.
GOOD : Nowadays I prefer classical music.
BAD : Are we allowed to play a pop music?
GOOD : Are we allowed to play pop music?
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Music is an uncountable noun: 'Her hobbies are gardening and music.'
2
BAD : After leaving school, he joined a music band.
GOOD : After leaving school, he joined a band.
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(jazz/rock) band or (pop/rock) group (NOT music band ): 'The band's new album has just been released.'