bar line vs musical notation

bar line and musical notation both are nouns.

Word	Noun	Adjective	Verb	Adverb
bar line	Yes	No	No	No
musical notation	Yes	No	No	No

As nouns, musical notation is a hypernym of bar line; that is, musical notation is a word with a broader meaning than bar line:

bar line: a vertical line before the accented beat marking the boundary between musical bars
musical notation: (music) notation used by musicians

Other hypernyms of bar line include line.

bar line (noun)	musical notation (noun)
a vertical line before the accented beat marking the boundary between musical bars	(music) notation used by musicians