As a result of the ever-changing definitions of music genres, there are quite a few rock bands that were once considered metal, but aren't anymore.

We've argued numerous times that heavy metal, as a genre, was "invented" when Black Sabbath released their self-titled debut album in 1970. But, there were several other rock groups making music that was heavier than anything people had ever heard around that time, too.

These particular groups were called "metal" back then by some, although we typically classify them as hard rock when we hear them today.

This happened as rock and metal started branching out in the late '70s and early '80s as well, especially with the development of hair metal in the late '80s. A lot of those bands are simply considered rock groups now, but because their sound was so unique at the time, they were dubbed metal.

READ MORE: 16 Bands + Musicians Considered Pioneers of Heavy Metal

Of course, as more metal subgenres such as thrash, death and other forms of extreme metal developed, it seemed silly to think of Motley Crue as a heavy group. But they were, at least at the time.

One of the musicians even told the Los Angeles Times, “A lot of heavy metal is ugly and sick. Some of those musicians are real weird. We’re not that way."

We rounded up a gallery of some bands that were considered metal at one point in time, even if they aren't today. To support the claims, we provided examples of either times they were called metal in the media, or when the musicians themselves acknowledged the label.

10 Rock Bands That Were Once Considered Metal, But Aren't Anymore

These rock bands were considered metal back in the day, but aren't anymore.

Gallery Credit: Lauryn Schaffner

The Best Metal Album of Each Year Since 1970

See Loudwire's picks for the Best Metal Album of Each Year Since 1970

Gallery Credit: Loudwire Staff

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