quarter note vs musical note

quarter note and musical note both are nouns.

Word	Noun	Adjective	Verb	Adverb
quarter note	Yes	No	No	No
musical note	Yes	No	No	No

As nouns, musical note is a hypernym of quarter note; that is, musical note is a word with a broader meaning than quarter note:

quarter note: a musical note having the time value of a quarter of a whole note
musical note: a notation representing the pitch and duration of a musical sound

Other hypernyms of quarter note include note, tone.

quarter note (noun)	musical note (noun)
a musical note having the time value of a quarter of a whole note	a notation representing the pitch and duration of a musical sound