One common error in English is confusing the words " music " and " song ".

Music refers to the category in general and song refers to one specific piece of music.

For example, " I like pop music." That's pop music in general.

Michael Jackson 's music is famous throughout the world.

Again, " music " refers to Michael Jackson 's music in general.

" Billy Jean " is a song by Michael Jackson. " Thriller " and " Beat It " are two more songs.

In this case we use " song " because it's a specific piece of music.

" Music " is uncountable, so there's no plural.

" Song " is countable. You can say, " I like three songs on this CD," but it's incorrect to say " I like three musics on this CD,"

because " music " can not be plural.