play along vs music

play along is not a noun while music is a noun.

Word	Noun	Adjective	Verb	Adverb
play along	No	No	Yes	No
music	Yes	No	No	No

play along (noun)	music (noun)
	musical activity (singing or whistling etc.)
	punishment for one's actions
	any agreeable (pleasing and harmonious) sounds
	(music) the sounds produced by singers or musical instruments (or reproductions of such sounds)
	an artistic form of auditory communication incorporating instrumental or vocal tones in a structured and continuous manner

play along (verb)	music (verb)
perform an accompaniment to
cooperate or pretend to cooperate