Originally Posted by Unknown Soldier

Not quite, metal is a sub-genre of rock and metal originates largely from blues rock and psychedelic rock. These influences were gradually faded out by the end of the 1970s and early 1980s. Also at this time what was considered heavy metal and hard rock, had very little difference in terms of which was louder and it came more down to subject themes. Since then though and largely with thrash and extreme metal, metal has largely become more abrasive and more diverse than it ever was.