There's metal that's melodic, but is there a Melodic Metal sub-genre? There's glam metal, grunge, melodic death metal, melodic metalcore, power metal, just to same a few, but I've never heard of "melodic metal"
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AOR is an interesting genre for me because I don't know that much about it. I'd choose the "Adult" over "Album" in the acronym, it's slightly older, prog. influenced musicians that wanted to play a more mature and popular style of rock music, instead of NWOBHM, Thrash or Hair Metal which was more youth oriented. Melodic aspects can be heard in all of these.