eighth note vs musical note

eighth note and musical note both are nouns.

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

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

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

Other hypernyms of eighth note include note, tone.

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